I have coins from Australia, India, and Mexico that I would like to convert to US dollars. Unfortunately, Travelex doesn't take coins, nor do any of the banks I've checked with. Does anyone know where I can exchange these coins in the US?

I have about $10-12 Australian dollars worth of coins. As I'm not going to Australia anytime soon, I'm leaning towards taking anything I can get.

Alternatively, are there any reputable charities that will take these coins if I mail them in?

I also see from previous Flyertalk postings that there is a machine at Portland PDX which will take coins - anyone know what currencies it accepts (and if Australian dollars is on the list)?