A patron who thought he was stiffing a server at Holiday’s Restaurant gave her more than he bargained for.

“I still remember where he sat,” says Jeanie Gonczy, “and he was just very, very dissatisfied with everything. He was having a bad day, I think. A commercial came over the radio, and he got very furious that he was paying money to sit here and listen to it.”

When Gonczy went to clean the table, she found her tip: two quarters. And one of those was a fake: “I could hear the difference when I dropped it in my apron,” she says–it sounded like aluminum. Gonczy has an ear for coins–she collects them.

“The date on the coin was 1964,” she says. “That’s when they quit making silver quarters, and counterfeits were made to pass off to people who collected them.” In the kind of ironic twist familiar to collectors of almost anything, the fake quarters are now collectors’ items themselves. Gonczy figures hers is worth about $45, but she’s not planning to sell. “I still have it,” she says–“and I also have a 1964 silver quarter.”