If you're a true fan of Mickey Mantle, autographs may seem just the way to show everyone your feelings, but be aware of forgeries. His autograph is one of the ten most often forged sports autographs thanks in large part to the famous forgery ring that swept the country in the 1990s and resulted in the FBI's Operation Bullpen investigation. The good thing is that Mickey Mantle autographs are now among the most studied of all time and authenticated signatures are readily available.
Over the years, fans may have collected Mantle autographs on baseballs, programs or rosters. When he started on the baseball card show circuit in the 1980s, he signed thousands of baseballs, photos, jerseys and other nice items.
If you see a company or person selling Mickey Mantle autographs on 3x5 cards, these can be somewhat suspicious. First, it's not the ideal piece of memorabilia, and second, when people went to autograph signings, they usually took something other than 3x5 cards – usually something related to baseball. Some 3x5's are probably authentic, but it's safe to say that many are forgeries.
Mantle was very professional at knowing where to sign posters, balls and photographs, so that they would look as good as they could. If you find a poster, magazine cover or photograph that supposedly has Mickey Mantle's signature, it may not be his if it's signed in an area where it's difficult to read. Either that or he signed it somewhere away from the field or scheduled autograph signings, while someone caught him in a hurry.
Mickey Mantle autographed items are some of the most expensive you'll see today. PSA or JSA authenticated items are the safest bet. There are plenty of non-PSA or JSA Mickey Mantle autographs to be found and many are likely the real deal but you will want to check with a reputable and knowledgeable collector or vendor to make sure that what you're getting is not a forgery.
Mantle's signature changed from the early portion of his career to the unique, flowing style so often seen on Sharpie-signed photos and new official baseballs he penned in the 1980s and 90s.
If you're buying non-professionally authenticated autographs, try to determine when and where the autograph was signed, and if you can't find out any of this information, choose another autograph or check with a reputable vendor. You can also compare undocumented Mickey Mantle autographs with several that you know are legitimate. They should not match exactly, since no one signs their name exactly the same way every time they sign it. But likewise, they should not differ a lot from legitimate autographs. In addition, signatures on bats, balls and jerseys are harder to determine authenticity on, since they are an uneven surface for signing, but these are more expensive items, and you will want the have the authenticity checked by an expert.