When is an ordinary-looking $5 coffee cup worth $10,000? When it's John Lennon's coffee cup, and it's the last one he drank from before he was murdered. But how can any buyer be certain of an item's back story? Only 6 percent of all signatures from the Beatles are real, according to CNBC's "Treasure Detectives" host Curtis Dowling —yet 15,000 of them sell per month.
As Dowling explains, an item's provenance—where, when and from whom it originates—means everything to a collectible's value. But how can you know the story attached to the item is true?
The selling of fakes that trade on famous names is serious business: In the 1990s, an operation by the FBI, U.S. Attorney's Office and IRS targeting fraudulent memorabilia resulted in the dismantling of 18 forgery rings. According to the FBI, most experts agree that in celebrity memorabilia sales, there's more than a 50 percent chance of forgery.
A photograph, a believable story or a letter of authenticity are not always enough. Dowling cites an example of the couple who got a scarf from Elvis Presley in a 1976 concert. Although that part was legitimate, the couple then sold the same "Elvis concert scarf" for $1,000 around 1,000 times.
So—still thinking about buying that celebrity personal effect, or a prop or wardrobe piece from a favorite film? In this web-exclusive clip, Dowling explains what buyers can do and ask to protect themselves from paying big bucks for a phony.