This weekend working out I came across an article in Businessweek about the environmental benefits if we put dormant coins back into circulation. BW had sourced a press release from Coinstar, the makers of those coin counting machines in your local grocery store.
The environmental savings are quite impressive considering it would put on average $90 into your pocket. Of course you could visit your nearest Coinstar machine or visit a bank that offers free change counting, for example Commerce Online.
One other interesting tidbit is that it costs the U.S. Mint 1.3 cents to make a penny and 7.7 cents to make a nickel.