Any time we come back from a trip with foreign currency, we place it in a little woven container that grandma bought us in 1984, or so. We returned on Tuesday from a friend's wedding in Jamaica - our first time there. After emptying our pockets, we put the Jamaican coins in our little container (which we had totally forgotten was also from Jamaica), and started looking at all the currency we'd collected over time. Then we thought of what other people might do with bits of money after returning home, and we immediately remembered Carlos & Danny's display in their wonderfully rich, bright kitchen.
And here's my little way, a method I've stuck to for years:
What do the rest of you do with leftover foreign currency?