I don't usually have a ton of leftover foreign cash when I return home. I take the bulk of my currency and pay down my hotel bill, this is cheaper than converting it back to my home currency and saves me foreign currency conversion fees on my credit card. And sometimes I'll take a small handful of cash leftover once at the airport and look for appropriately priced duty free.

But inevitability to have some leftover cash.

What do you do with yours? Do you convert it when you get home? Do you keep it for future trips? Give it away to friends traveling to the same destinations?

In my safe at home I have Baht, HKD, CNY, Yen, Euros, GBP, etc. I will certainly use them again, and I grab the currency before a trip. But I look at the stash, "that's real $$$ and it's just sitting there." And I was wondering whether anyone does anyhing else with theirs?