If you live in a country that gave up a national currency for the euro, you may want to check the cracks and crevices of your sofa.

More than 15 billion euros (C$21.5 billion) of outdated banknotes and coins in the euro-area have not yet been handed in and exchanged for euros – roughly the annual cost of Latvia’s imports. Just under half of the region’s hidden treasures are stashed away in cash-loving Germany, even though it got more than a decade of head-start over newer euro-adopters such as Latvia and Lithuania.

About a third of the total amount knocking around the region is now worthless, with 12 national central banks having given up their coin redemption duties and the deadline for exchanging banknotes having expired in France, Italy, Finland, and Greece. Luckily for Germans, there’s no need to rush – the Bundesbank has said it will “indefinitely” exchange “unlimited amounts” of deutschmarks, while the Bank of Portugal stopped exchanging coins at the end of the same year the euro was adopted, rendering worthless 48 percent of outstanding escudos.

Deadlines for cash swaps have been a source of annoyance for some euro-area residents who missed the chance to exchange their fortunes. The Bank of Italy was ordered to redeem 2.5 million euros worth of liras last year after members of the public complained to the country’s constitutional court that the central bank had unexpectedly moved up its exchange deadline by three months in 2011.

With assistance from Maria Tadeo, Mark Deen, Corina Ruhe, Alessandro Speciale, Ott Ummelas, Joao Lima, Paul Tugwell and Lorcan Roche Kelly