If you have a Babe Ruth baseball card or Bambino-autographed ball lying around in your attic, it might be worth a pretty penny. As Atlas Obscura reports, a rare Babe Ruth rookie card just sold for more than $130,000—roughly double the auction house’s original estimate.

Ellen Kelly, a hospital receptionist who works in Keyser, West Virginia, discovered more than 110 vintage baseball cards inside of an old piano she had purchased from her family’s estate sale. “Best $25 I ever spent,” she told Sports Collectors Daily.

The most valuable of the bunch was a Babe Ruth card that showed the player during his rookie season while pitching for the Boston Red Sox team. It was still in good condition, except for a small crease running down the middle. The card belongs to a set called “M101-4,” which, according to Atlas Obscura, “ushered in a transition from the lithographic art of older cards to black and white photography.”

The piano originally belonged to Kelly’s aunt, and she believes her dad or uncle hid the cards inside the instrument to prevent them from being tossed out by her aunt. Though she uncovered the cards in the '90s while getting the piano repaired, she didn’t have the Babe Ruth card appraised until recently.

“Different people had offered to do it before for me, but it didn’t feel right,” Kelly said. “Someone offered me $40,000 for the Babe Ruth card and I thought, ‘That’s Babe Ruth, he’s worth more than that.’”

The staff over at Goodwin & Co.—the auction house that ultimately sold the baseball cards—were just as surprised as Kelly to discover the rookie card’s actual worth. “We thought $60,000 to $75,000 was a fair estimate for this card. We are thrilled to see a six-figure final sale price,” Steve Bloedow, the Media Director of Auctions for Beckett, which oversees Goodwin's sales, told Sports Collectors Daily. “The buyer has asked to remain anonymous and we are respecting their request.”

Kelly also netted about $4400 for the rest of the cards—not bad for a $25 investment.

[h/t Atlas Obscura]