Instructions
Examine the collectible item closely if you have real-world access to it. If it's an album, CD or any other mass-produced item, look for label identification, sleeves or packaging and other information about the release. Beware of no-name record labels or labels which you've never heard of when you are knowledgeable about that artist -- chances are the item is fake, pirated or bootlegged.
Inspect autographed items in detail. Compare the autograph to other known legitimate autographs by the same artist. The signatures should be very similar and smooth. Look for shakiness, forced lines or misspellings, as these are all signs of forgeries. Also pay close attention to the item itself -- if, for instance, it's a Jimi Hendrix autograph on a 1990s-era guitar, you know it's a forgery.
Ask for proof of authenticity from the vendor if the collectible is a one-of-a-kind item. If the item is legitimate, the vendor should have no problem showing proof. Also ask where and how they acquired the item. If you are planning to purchase the item, ask if the vendor will put it on hold for a day or two, then use that time to research the vendor's honesty, as well as the history of the collectible. Don't buy the item if anything about it or the vendor seems potentially fraudulent.