Remember that old shoebox of baseball cards your grandfather gave you? Well, for some, those boxes could represent a fortune—many times going unnoticed over several lifetimes. And if you do have a sizable collection of sports cards or memorabilia, odds are your investment is completely uninsured.

That is where Michael Osacky can help. Dubbed “the Dean of Cracker Jack Baseball Cards” by Forbes, the Chicago native specializes in vintage baseball cards and sports memorabilia. Not only does Osacky’s company, Baseball in the Attic, seek out and purchase memorabilia, he also specializes in appraising personal collections.

“The insurance carriers don’t allow homeowners to say how much their collections are worth,” said Osacky. “But I create a formal, written appraisal that providers can utilize.”

Osacky, who will be evaluating two “significant” collections in Key West this Thursday and Friday, said he often finds people who stored vintage cards and memorabilia away, never realizing their true value.

“I had an older couple that had an entire set of 176 Cracker Jack Cards,” said Osacky. “Keep in mind only one per box came with Cracker Jacks in 1914 and 1915. They thought the cards were worth about $2,000, but when I told them they were valued at around $80,000, they just started crying. I then recommended they use an armed guard escort them out of the building,” he said, laughing.

Although baseball and sports card collections reached a pinnacle in the 1980s and ’90s, Osacky’s ideal client possesses cards and memorabilia ranging from 1870 to 1970. Think Mickey Mantle, Babe Ruth, Ty Cobb and Willie Mays and you will be on the right track.

“I especially love anything that has a story with it,” said Osacky. “The best stories are when someone has something that grandpa got at Yankee Stadium as a kid, or items that were passed down from generation to generation.”

Baseball cards are not the only items that carry potential value. Osacky said some of his personal favorites are vintage Chicago Cubs Spring Training programs, early 1900 baseball pennants, baseball bats, uniforms and autographs.

“Autograph books were popular in the 1940s and ’50s,” said Osacky. “It was much easier for kids to get players to sign autographs before and after games and these things would be filled with huge names. But the coolest thing about these books was the first page had the kid’s name and information and really tell a neat story today.”

For those who are skeptical, a simple Google search of a Mickey Mantle 1952 Topps rookie card should be enough to prompt a thorough search through storage bins and shoeboxes. That card is often valued well above $1million, while the rare 1909 Honus Wagner tobacco card has fetched close to $3 million at auctions. For more on Osacky and Baseball In the Attic visit www.baseballintheattic.com or by calling 312-379-9090.