When you come back from an international trip, you may be left with a handful of coins in a currency you can't spend at home. While most foreign exchange companies and large banks are willing to buy back international bills, it can be harder to find a home for unneeded coins. Unfortunately, you'll probably have to take a loss on the coins' face value in order to turn them back into money you can use.
At the Airport
Because it can be a challenge to exchange foreign coins for American money or goods in the States, many travelers choose to use their foreign currency at the international airport before boarding the flight back home. While currency exchange stores at the airport aren't always willing to take the coins, you can spend that money on goods and services, such as a shoeshine, last-minute souvenir or a snack to eat on the airplane.
The World Coin Gallery provides a venue for trading your foreign coins with other interested parties, often for currency from another country. Coin collectors are often interested in foreign money too, but be warned that you'll rarely get face value on newly minted coins. Other places you'll find people who might be interested in buying your coins are garage sales and online ads, and local schoolteachers that might want them for their classroom; or you can donate your coins to a local child who is just starting her own coin collection.
You might get lucky and have a chance to exchange your coins with others while winding up your vacation or after you get home. While still traveling, connect with other Americans who are in-country and offer to exchange your local coins with them for U.S. currency. Or when you get home, seek out friends or family members who are planning an international trip and exchange the coins with them in advance of their travels.
Travelers who are unable to exchange their coins for goods or services can donate their money to UNICEF's Change for Good program. UNICEF accepts foreign coins mailed to the program and sends you back a letter of recognition. Some airlines also collect spare coins for UNICEF on the plane, or accept the coin donations in their airport lounges; check the airline or UNICEF website to find out if this is an option for you.
You also have the option of shipping your coins to Leftover Currency, a UK-based company that will exchange the coins for the currency of your choice. You'll lose a bit of money on the exchange rate and the shipping costs, but the end result is still a lot better than putting the coins in a drawer and never getting any worth out of them at all. And Leftover Currency is fast – once they receive your coins, the exchanged money will be back on its way to you, by the method of you choice, within about five business days.