If you've had your coins for awhile they've probably gotten tarnished or discolored.
If you go down to you local Wal-Mart (Retail Store- for those not in the US), mosey down to the Automotive section and pick up some liquid metal polish. It'll probably be in the car cleaning section. It works great for all metal tricks for shining them
up. Coins look like brand new after a few rubs.
I have all my half dollars, silver dollars, gold dollars and quarters shining like they are fresh off the mint. Also used it on some of my foriegn money I got while travelling abroad. It's also a good way to remind you not to spend it.... your less likely to forget its your working coins if its sparkling at you (gimmicked or non).
Works great on the S&S or D&P too! The D&P tarnishes quicker than any other coin I have for some reason. Must be the cheap metal!
I personally use Blue Max Liquid Metal Polish
. Works great for all your metals... ie. matchbox penetration.
P.S. Anyone notice the State quarters feel cheaper than the Eagle quarters? I use the Eagles b/c they shine up nice and don't feel like plastic.