Understanding how to grade a sports card is vital for both new collectors and grizzled veterans of the hobby.
While most turn to third-party card grading services (such as PSA, SGC, or Beckett), knowing what a raw card will earn for a grade is essential for collectors.
This piece discusses some pros and cons of third-party grading companies while offering collectors a lesson on professional grading.
This resource will provide everything you need to evaluate your cards just as the professional graders do.This knowledge will help spot raw cards for sale and allow you to develop an expected grade on the spot.
What Is Card Grading?
Card grading is the process of having a professional, third-party evaluator determine the overall condition of your sports card.
Third party card grading companies help you determine whether your card is authentic or not, while also providing an overall condition 'grade' for your card.
Card grading companies have provided a legitimacy to a hobby that was once governed by handshake agreements regarding a card's condition.
How Does Card Grading Work?
A collector sends their cards to one of the third-party graders, which provides a condition grade (1-10) for a small fee.
Upon receipt of your cards, a card grader will examine them, evaluating their authenticity and condition.
After assigning a grade, cards move to the grader's encapsulation department.
Encapsulators insert the card into a thick plastic holder (aka 'slab') with a label displaying the grade. The cards are then packaged and shipped back to the collector.
This is a great video that steps behind the scenes of the SGC grading process
Why Should I Get My Cards Graded?
Cards graded by experts will often bring a higher price than those without.
A professional opinion of your card's condition can make all the difference when it comes time to sell your cards.
Buying a raw, ungraded card online can often be a crapshoot, as sellers can manipulate photos to conceal major flaws.
Thus, most collectors would rather buy a graded card, since they know exactly what they are buying.
Should I Get My Card Graded Or Not?
There are many factors that determine whether you should grade a card or not. The most important are the costs to grade and the card's value.
If the costs to grade a card are higher than the actual value of the card, it doesn't make much sense to submit it for grading.
Also, if the estimated value of your card when graded is less than the value of the ungraded card plus the costs to grade the card, don't get it graded.
Yet, some collectors like to pay a premium to have cards in their collection evaluated by third-party grading companies.
Understanding Condition & Card Grades
All sports card grading companies use the same card grading terminology to evaluate a card's overall condition.
Here are the condition terms ranked from the best overall condition to the worst.
Near Mint to Mint
Note that this is a generic classification system that is standard throughout the industry.
As we explore in later sections, the third-party grading companies have their own guidelines.
But, the actual condition names are consistent across the grading companies.
Also, it is important to note that the age of cards makes no difference in card grading.
A 1909 T206 card that is graded as Mint is held up to the same standards as a 2018 Topps card.
It's a common misconception, but Mint is Mint and Poor is Poor, no matter the age of the card.
Key Characteristics of Grading
Centering is one of the key inputs to evaluating a card's grade. For some collectors, a card with near-perfect centering is an absolute necessity. Although some are willing to overlook centering in hopes of a card with pristine corners and little surface wear.
Whatever the case, centering is an important part of the grading process.
One can typically eyeball a card's overall centering. It might be hard sometimes to tell if a card has perfect 50/50 centering (like the Trout card below), but it's fairly easy to tell if something is quite off-center.
Centering is a mathematical process, and professional graders measure the distance of the outside border to the edge of the card on the top, bottom, and left and right.
If the distance is exactly the same for all four measurements, a card is considered to have perfect centering.
Here's a great little spreadsheet that someone from the Collector's Universe built to help in calculating the actual centering percentages.
It's somewhat simple: measure the top and bottom borders in your preferred unit (mm, inches, whatever), add the two and then divide the top border measurement by the sum.
Here's a Jordan Rookie with some clear centering issues (it actually received a Mint (9) rating from PSA but with an OC or off-center qualifier).
According to PSA, a card that gets a Mint (9) grade, has to have centering of 60/40 to 65/35 on the front.
If we measure the left and right borders, we find that this Jordan card actually has 70/30 centering.
So, even though it met all of the requirements of a Mint card, its centering led it to receive a 9 (Mint) grade with an OC (or off-center) qualifier.
Note that the different grading companies have slightly different standards for centering.
PSA is slightly more lenient than SGC.
A card that is considered "Gem Mint" must have four perfectly sharp corners and is a general standard across grading companies.
What you and I think might be perfect corners, might not cut the grade with PSA or SGC, as the graders are looking at the card under magnification to get a closer look at the card.
Any slight imperfection on one corner will move you down the grading scale, while multiple corner issues will move you even further down the scale.
Cards that are graded Fair or Poor typically have severely rounded corners.
Most collectors don't normally think of the surface of a card when considering a card's grade, but this is an important factor.
A perfect card with sharp corners yet with some fingerprints or dirt on the surface will never earn a Gem-Mint rating.
As we discuss later, using a jeweler's loupe and/or a blacklight can also help get your eyes on some other unidentifiable surface issues that your naked eye can't pick up.
Surface problems can come in all kinds of forms, but some of the more common issues that will downgrade a card's grade are wax stains, print defects, focus imperfections, scratches, scuffing, ink marks and creases.
Some surface issues might be potentially cleaned from the card, like dirt or fingerprints, while the others are unfortunately just something you'll have to deal with.
Lower-graded cards will have these problems in increasing numbers and severity.
As we also note later, PSA has its own 'qualifiers' such as 'ST' (or stain) that will be added to a card's typical grade.
A card's edges (or borders) are also an important factor when considering a card's overall grade. A card in Gem Mint or even Mint condition should have sharp edges with no signs of chipping.
Sometimes it can be hard to see problems on a card's borders with your naked eye. Thus a loupe or other type of magnifying glass is needed in order to get a closer look at the card.
Cards in lower grades typically have significant border wear with potentially chipped edges on the card.
The Card Grading Companies
Let's take a quick look at the card grading companies. Note that newer entrants aside from the big three such as CSG have entered the mix, but for now we will focus on the three most popular grading companies - PSA, Beckett and SGC.
Quick note, we put together a list of card grading companies to avoid (many which have gone out of business).
Here is an overview of all of the major graders you need to be concerned with:
Professional Sports Authenticator (PSA)
PSA is the largest and most highly respected card grader on the market. They are also part of a (formerly) publicly traded company called Collector's Universe. Many might argue the point, but PSA graded cards sell for a premium in the resale market versus other third party graders.
Cards are graded on a 10 point scale from 1 through 10, with 10 (Gem-Mint) being the best. Note that achieving a perfect 10 Gem Mint grade is quite a challenge.
Cards that are graded as 'Authentic' are known to be genuine, but because of an alteration or other defect, the grader was unable to provide a numbered grade.
PSA Grading Scale
Gem Mint (GEM-MT)
Near Mint to Mint (NM-MT)
Near Mint (NM)
Excellent to Mint (EX-MT)
Very Good to Excellent (VG-EX)
Very Good (VG)
PSA also has 'qualifiers' which can be added to a numbered grade---such as OC (off-center) or ST (stain). According to PSA, a “Qualifier” is a term used when "an item meets all of the criteria for a particular grade but may still have one significant flaw".
List of PSA Qualifiers
OC - Off-Center
ST - Staining
PD - Print Defect
OF - Out of Focus
MK - Marks
MC - Miscut
Qualifiers tend to bring a card down on average one to two grade levels in the resale market--for example, a PSA 8 card with an OC qualifier would likely sell for what a PSA 6 or PSA 7 card would go for. Note that when submitting cards for grading, one can request a grade with 'no qualifiers'.
UPDATE: PSA has recently announced that it would no longer automatically apply qualifiers to graded cards.
One of the reasons for PSA's market dominance, is the well-documented population reports for graded cards, along with the impressive set registry, which allows collectors to submit and track their collections on PSA's website.
Costs for submission vary but start at $20 for regular card grading. Due to the popularity of card grading in recent years, turnaround times on submissions have been severely impacted.
PSA is a division of Collector's Universe (CLCT), a publicly-traded company. (UPDATE, CLCT has recently been acquired by a private equity consortium).
PSA has been on a remarkable rise since 1991, a year which marked a tumultuous time in the grading company's early years; allegations arose that it knowingly ignored an obvious trimmed 1909 T206 Honus Wagner card. Even ignoring that black mark on PSA's history, I can assure you of one thing--the third-party card graders are not always right! You can read an example of this in our lengthy piece on strip cards.
Sportscard Guaranty Company (SGC)
If PSA is numero uno in the grading community, then SGC is a close second. SGC is popular with some vintage collectors who prefer the black inserts used in the SGC cardholders. Still, PSA clearly has the edge as the hobby's favorite and is the preferred company to use for maximizing resale value.
As for quality, SGC has always been very consistent with its grading, maybe even with a better reputation than PSA. But in the end, all of the grading companies will make mistakes; they are after all only humans.
The days of artificial intelligence (AI) and algorithmic grading aren't here (YET) so we have to live with the flaws that human grading brings to the table.
There will always be cards that appear under or over-graded; in the former, most just chalk it up to the grader having a bad day. I wish there were more uniformity among third-party graders, but until those bots start grading cards, it is what it is.
Side note, I saw someone in a forum I visit frequently mention this about the inconsistency with grading and I thought it was spot on. THE ROBOTS ARE COMING (maybe?)
The grading industry is long overdue for a major overhaul. I hope that whatever technology will be used corrects some or all of the current problems. I really don't want to hear about the subjectivity of grading. I want to hear about a system that grades cards correctly and will deliver that same grade no matter how many times a card is reviewed. I don't want to hear stories about cards being submitted three times and getting three different grades. If it can't be done right, then it shouldn't be done at all.
BIG NOTE SGC has recently moved to a new grading system!
From herein on in, they are only utilizing the 0 to 10 grading system that PSA uses.
Previously they used to include their 0 to 100 grade and the equivalent PSA 0 to 10 grade (see Ripken rookie card above for an example of this).
Now it will only be a 0 to 10 rating. In addition, they went from their custom forest green color to new black bold lettering (see 75 Topps Ryan below).
I can tell you that I don't like it personally, and most in the hobby don't either. I think the numbering grade change is good, but the color change completely changes their identity.
UPDATE OCTOBER 2022 - I've definitely come around on THE BLACK SGC Slabs. I think they look pretty good now.
Note that SGC is also introducing a new scanned registry which could be a game-changer, but it all comes down to execution and I worry about SGC's ability to do this effectively.
Beckett's Grading Services (BGS, BVG, and BCCG)
I haven't used Beckett as much as I have SGC and PSA, but in my experience, the grading consistency is quite good. The problem is that PSA and SGC tend to be more widely utilized with vintage cards, thus making Beckett a lower-tier grader for both modern and vintage cards.
In addition, Beckett itself has three different grading subsidiaries: Beckett Grading Services (BGS) for cards from 1981 to the present, Beckett Vintage Grading (BVG) for pre-1981 cards, and then Beckett Collectors Club Grading (BCCG) which is a lower-tier grading level that Beckett uses and is generally not well regarded.
UPDATE - Beckett is no longer accepting submissions for BCCG
BGS uses a different system that helps differentiate it from other grading services. Cards are provided four different sub-grades based on the following criteria:
BGS then uses a 'black box' algorithm to take the subgrade scores to arrive at an overall grade. While the algorithm has never been revealed some have tried to crack the code.
"In summary: Corners is punished hardest, Centering next, Surface/Edges the least. How much the overall grade is better than the worst subgrade depends on which subgrade is the worst, and also depends on how much the other three subgrades are better than the worst subgrade, measured by diff (or the differential in subgrades)"
The scoring for BGS is mostly similar to industry grading (1-10) scales with one exception. A BGS 9.5 is known as a Gem Mint, which would be similar to a PSA 10 or SGC 9.5.
BGS also has a 10 score, which they call 'Pristine,' meaning that a card scored a 10 in all four sub-grades. BGS now actually labels the card with a black label, calling it 'BGS Black.'
I think this whole Pristine thing is a bit confusing and I think the whole thing sort of puts off many collectors. Nevertheless, a Pristine-graded card does often hold a premium.
Just remember that a BGS 9.5 is equivalent to a PSA 10 or SGC 10. Note that BVG or BCCG do not evaluate a card using sub-grades and thus do not have a similar 'Pristine' rating.
For vintage collectors, I wouldn't really bother with any of the Beckett grading services. I know some use BVG for vintage card grading, but PSA or SGC will generate better returns.
In addition, I know someone who just waited over a year to receive some card submissions back from Beckett.
What Is The Best Card Grading Service?
Most collectors will agree that the three best card grading companies are Professional Sports Authenticator (PSA), Sportscard Guaranty (SGC), and Beckett Grading Services (BGS and BVG).
PSA is the biggest and probably the most well-known grader in the hobby. While no concrete evidence exists, anecdotally speaking PSA graded cards tend to sell for a slightly higher premium versus comparable SGC, BGS, or BVG-graded cards.
As to who is the best grader, it's mostly subjective, as each collector has their own different experiences. For vintage cards, collectors tend to gravitate to PSA, SGC with BVG a distant third.
There have been some issues of trust recently in regard to third-party graders due to several trimming-related scandals. A lot of these issues surround PSA. Thus I know some collectors that will only grade through SGC now.
As to collectors, our recent survey found that in five different categories, PSA was found to be the best grading company in four of the five categories: accuracy, trust, customer service, and data quality.
PSA VS SGC Centering Differences
A Visual Baseball Card Conditon Guide
geM MINT (10)
According to PSA, to earn a pristine PSA 10 (or Gem-Mint) rating, the card must be a 'virtually perfect card.' The corners must be sharp, with no staining and original focus intact. Note that PSA does allow cards that are slightly off-center to earn a PSA 10 grade but not to exceed 55/45 to 60/40 in the front or 75/25 on the reverse. Below is a PSA 10 graded Ken Griffey Jr 1989 Upper Deck rookie card. You can see that the corners are pristine, and the card overall is in remarkable condition.
According to PSA, a grade of PSA 9 (or Mint) would be a superb condition card with one minor flaw, either a slight wax stain on the back of the card, a minor printing imperfection, or slightly off-white borders. Overall centering on a PSA 9 still needs to be within guidelines of 60/40 or 65/35 and 90/10 on the reverse. As shown with the 1985 Donruss Clemens rookie below, the card looks fantastic, but there are a few minor border imperfections, which result in the card only earning a 9 grade. SGC's guidelines refer to a Mint card as a score of SGC 9 and have most of the same sort of guidelines as PSA.
According to PSA, a grade of PSA 8 (Near Mint-Mint) is still a superb card at first appearance but after examination has a slight wax stain, slight wearing on corners, a minor printing imperfection, or off white borders. Centering has to be 65/35 to 70/30 on the front and 90/10 or better on reverse.
SGC's guidelines refer to a Near Mint to Mint card as a score of SGC 8 and have most of the same sort of guidelines as PSA although slightly less lenient on centering, noting that 65/35 centering or better is required.
We have below a quite nice-looking George Brett 1975 Topps Rookie card graded a PSA 8. The corners look pretty nice, but you can see some slight wear on the bottom right corner, along with a small red print defect on the bottom right corner, along with another small print defect next to the S in 'Royals'. This one was probably close to getting a qualifier (PD or print defect) but overall still a good-looking Brett rookie card.
According to PSA, a grade of PSA 7 (Near Mint) is still a very nice card on appearance, but there is some slight surface wear or fraying on the corners. Minor printing blemishes and wax stains are acceptable, although anything more significant would likely result in a qualifier. Centering guidelines are slightly loosened here as 70/30 or 75/25 on the front is OK. Thus, you might see some very off-center PSA 7 cards without any qualifiers.
SGC's guidelines refer to a Near Mint card as a score of SGC 7 and have most of the same sort of guidelines as PSA although slightly less lenient on centering, noting that 70/30 centering or better is required.
According to PSA, a grade of PSA 6 (Excellent-Mint) means that a card has minor wear on the corners, 80/20 or better centering, and no major flaws.
SGC's guidelines refer to an Excellent-Mint card as a score of SGC 6 and have most of the same sort of guidelines as PSA although slightly less lenient on centering, noting that 75/25 centering or better is required.
We have below a 1969 Topps Reggie Jackson Rookie card graded a PSA 6. The card is in overall nice shape, but that top right corner is a bit soft, as also noticed on the flip side of the card. Anything else wrong with the card would have likely led to this card earning a PSA 5 instead.
According to PSA, a grade of PSA 5 (Excellent) is still an attractive card, but may have light rounding of the corners, very light creasing, minor wear on the surface, and centering of no worse than 85/15.
SGC's guidelines refer to a Excellent card as a score of SGC 5 and has most of the same sort of guidelines as PSA but is a bit more specific on creases, noting that an SGC 5 graded card may have "one VERY slight surface or "spider" crease may on one side of the card"
Below is a 1909 T206 Rebel Oakes card graded a PSA 5. For a nearly 120 year old card, it's obviously in pretty nice shape, but we can see some wear on all of the corners. I think this might have actually been a generous grade (note that does happen a lot) but still, we can see the much lower condition from higher graded examples.
According to PSA, a grade of PSA 4 (Very Good - Excellent) means that a card's corners may be slightly rounded. Surface wear is also noticeable but modest. It may have light scuffing or light scratches. Some original gloss will be retained. Borders may be slightly off-white. A light crease may be visible. Centering must be 85/15 or better on the front and 90/10 or better on the back.
SGC's equivalent for a PSA 4 is an SGC 4, with criteria mostly the same, although SGC notes centering must be 85/15 or better.
Below is a PSA 4 card of the GREAT ONE, 1979-1980 Topps Rookie Card. There is undoubtedly some corner and border wear and those corners are lot more rounded than any of the higher grade cards we've examined so far. Other than that, the card overall is in pretty decent shape.
According to PSA, a grade of PSA 3 (Very Good or VG) has noticeably rounded corners (albeit not extreme), with printing defects, light creases, or small wax stains possible. Surface wear and edge wear are also common. Centering must be 90/10 or better.
SGC's rating is also a 3 for a Very Good card. Guidelines are similar to PSA and also note that stronger creasing may exist.
Here's a great card -- the 1954 Bowman Ted Williams as graded a 3 by PSA. The card has some obvious corner wear and some light creasing near the top left corner of the card. Can also see from the back of the card that there is some obvious crackling due to the aging of the card which would also bring down the grade.
According to PSA, a grade of PSA 2 (Good) indicates a card with apparent defects, usually significant corner and surface wear. Creasing is possible, along with staining, scratching, or scuffing. Centering must be 90/10 or better.
SGC's guidelines refer to a Good card with a score of SGC 2.
Here's a PSA 2 graded 1952 Topps Willie Mays. We can see the rounded corners and noticeable surface wear on the front of the card, along with some discoloration from age. There is also a minor crease running from the left middle side to the center of the card.
A grade of PSA 1.5 (Fair) is a card with extreme wear, likely rounded corners, can be scuffing, staining2, with one or more heavy cases. A Fair card is in pretty rough shape, but still intact. If there are missing pieces of the card it can't receive a Fair rating and would likely receive a Poor (or PSA 1 grade).
**Note that PSA changed their grading system to add half-point grades back in 2015, thus you might see older cards with a "PR-Fair 1" which would grade as a PSA 1.5 today.
According to SGC, an equivalent grade is an SGC 1.5 and has the same general guidelines as PSA.
Here's a Michael Jordan '86 Fleer rookie card as graded PSA 1.5 (Fair). We can see that the card has some obvious wear, with rounded corners, chipped edging, some creasing along the left edges and some discoloration on the back top and sides of the card--see that yellowing?
A PSA 1 (or Poor) graded card has many of the same qualities as PSA 1.5 (Fair) card --such as heavily rounded corners, discoloration, staining, heavy surface wear, creasing, etc, but the wear is much more significant in nature and as PSA notes 'the card has almost vanished in entirety'. So, I've heard someone say 'imagine if they rolled up the card in a ball--you have a PSA Poor'.
SGC's equivalent rating for Poor is SGC 1.
Here's a 1949 Leaf Babe Ruth (i love this card) which from a corner perspective has wear, but not terrible. It's that missing part of the front of the card to the left of Babe's hat and the roughness at the bottom near his name. Then we look on the back and whoa, it's a big mess, some sort of coffee or drink stain it looks like, but whatever the case it's definitely in bad shape.
How To Submit Cards for Grading
Each grading company has its own submission forms for grading.
Be sure to read all the guidelines before submitting to any grader.
PSA Grading Submissions
SGC Grading Submissions
BVG Grading Submissions
Costs of Card Grading
Sportscard grading prices work on a few key factors - card value, desired turnaround time, and the type of card graded.
The pricing schedule can confuse you if you haven't submitted a card for grading before.
In recent years, card grading companies have experienced significant demand increases.
This influx of cards led to big price increases, the halting of lower-priced services, and long turnaround times.
PSA Card Grading Prices
Things have improved at PSA of late, but we aren't quite back to pre-covid card grading pricing.
PSA is now offering Economy ($50), Regular ($100), Express ($150), Super Express ($300), and Walk Through ($600) Services.
In addition, for members of PSA's Collectors Club ($99 per year), PSA is offering even better deals.
$18 Bulk Pricing for cards valued at $199 or less, and $30 Bulk Pricing for cards valued at $499 or less.
It's good that the card grading companies are starting to provide more normalized pricing.
Yet, PSA's services are still cost-prohibitive for many collectors.
Check Out Our Sports Card Grading Calculator
A Closer Look At PSA's Grading Service Levels
PSA's cheapest card grading service - 'Economy' - starts at $50, for a card with a maximum declared value (*) of $999.
This $50 fee is based on PSA's standard turnaround time of 45-90 days. This is an estimate and can vary based on grading submission demand. If the declared value is up to $1499, this becomes a 'Regular' priced submission for $100.
PSA also has an expedited grading service - 'Express', which costs $150 and allows for a declared value of up to $2499 and has an estimated turnaround of 14 days.
You can also go for a 'Super Express' turnaround of 7 days (declared value up to $4999) for $300 or a 1-day 'Walk Through' for $600.
Upping the declared value will also raise the costs, all the way up to $5000 for a 'Premium Elite' submission with a max declared value of $100,000 and a 1 day turnaround---this will set you back $5000.
*Note, the 'declared value is what you estimate your card will be worth after PSA grades it. This is not an exact science and is mostly used for insurance purposes. Assuming that you don't abuse the system, PSA won't upcharge you if you are slightly off on value expectations, but it can happen.
Reminder that the PSA Collector's Club is a great deal and offers quarterly grading bulk specials where cards can be submitted at a discount.
SGC Card Grading Prices
SGC also followed PSA's lead in raising prices during the pandemic as demand surged, but thankfully order has been restored and SGC now offers one of the best values among all third party graders.
Current SGC pricing starts at $24 and is more affordable than both PSA and Beckett.
SGC's base card grading service is now much cheaper than PSA and starts at $24 for cards worth less than $1500. They also have bulk ordering priced in on anything with a declared value at less than $1500.
Thus, for example, if you have 20 cards to grade with SGC (all worth less than $1500), you would only pay $20 per card.
Like PSA, they also offer higher-priced submissions based on turnaround time and declared value, yet across the board, SGC remains a great value.
Beckett Card Grading Prices
Beckett also shut down many of its lower priced grading offerings during the pandemic, but like PSA and SGC has been restoring service.
Beckett recently introduced new pricing tiers, with the cheapest grading service now at $20 per card (without subgrades) or $25 with subgrades.
The table below details Beckett's standard pricing across various turnaround times. Note that they also offer discounts on bulk submissions.
Good news- Beckett recently introduced periodic collector's specials based on bulk submisssions - $22 per card (with subgrades) if you submit ten cards or more and $18 per card for bulk submissions without subgrades.
It's clear that SGC and Beckett are now trying to outmaneuver the giant PSA in terms of pricing.
If you look at Beckett's submission form, you'll see that there is a declared value column. Note that this declared value number is determined automatically based on the various service levels for PSA and SGC, yet with Beckett you'll need to calculate grading costs based on the insurance value table below:
Declared Value Fee
Add $11.00 for each additional $1000 in declared value (or portion thereof)
Thus, let's say we are submitting the following card:
1952 Mickey Mantle Topps - Value $100,000 -- we want the standard turnaround.
This would start at $15 + $1,100 (for insurance) = $1,115 + ground shipping of ~$22 - or $1137
Tools Needed To Become An Expert Card Grader
Grademaster Centering Tool (or just a Ruler)
First, you don't NEED this, as I noted previously, you can just measure the borders and use this spreadsheet to help calculate the percentages. But I have heard good things about this Grademaster tool so it seems really helpful and thought I would give it a plug here.
I've also heard of some people using a sewer's Omnigrid, a plastic measuring grid. So either one is totally not necessary, as a ruler might be everything you need.
Jewelers Magnifying Loupe
I bought one of these from eBay and it's just like what jewelers use and it's only $5--it has an LED light and magnifies things up to 60x their size.
Good thing is that it's portable, so if you're going to a store or your local card show, you can bring it along for the ride.
Surfaces are one of the key inputs to evaluating a card's grade, so if the surface of the card is dirty or has fingerprints, it will receive a lower grade.
Carefully wiping the card clean with a microfiber cloth such as these can help avoid an unnecessary low grade due to a dirty surface.
Note that I also really liked this discussion on the Beckett forum about doing your own card grading. They also discuss getting a blacklight, which can be very helpful in looking at surface issues along with helping identify if you might have a reprint/fake card on your hands.
I bought this blacklight off eBay and this is all you really need in order to tell if your card is printed on newer or older vintage paper.