Sell it here or post it on craigslist. I always see people asking for currency when they are going to other countries so this is good for you
See if someone you know has a friend in the military stationed over there. If they are sending a care package or something these can be slipped in. Flat rate priority boxes go back and forth all the time, which would not be cost effective for a small amount, but easy to put into a box of other stuff. I came home with too much yen (found a 10,000 and 5,000 note I'd stuffed in a book of all things, wish I'd find that sort of thing more often...). Sent them to a friend and she mailed me back some goodies and cash. But notes were easier to manage.
That's the plan. If a bargain bin has a 500 yen for 25 cents and a 50 yen for 25 cent, the 500 yen is mine and the 50 yen is left in the bin. Same with Canada 1 & 2 dollar coins, 1 & 2 euro coins and 1/2/5 Swiss franc coins.