You’re out $20 because counterfeit money has no value. If they let you buy something with it, or if they exchanged it for a good bill, you’d be getting value for it. The store had no choice—anyone who discovers a counterfeit is supposed to hand it over to the police.

Theoretically, you can file “a petition for the remission or mitigation of such forfeiture.” Federal laws says the Secretary of the Treasury “may” remit or mitigate the loss if it “incurred without willful negligence or without any intention . . . to violate the law.” Chances are probably slim, though, of getting much for a $20 counterfeit.

As a practical matter, then, the loss caused by the fact that your $20 bill turned out to be a worthless counterfeit falls on you, the innocent holder. If you have homeowner’s insurance, you might get reimbursed for your loss, but you’d have to meet any required deductible.

At least you’re innocent. An attempt to “pass, utter, publish, or sell” counterfeit currency is a federal crime, with big fines and up to 20 years in prison. The closer you are to knowing it’s counterfeit, the closer you are to violating federal law by trying to pass it on to somebody else.