You really don't want to do anything to to them. If they're rusty, that's just the way they are now. Store them in a dry place. Cleaning will do more damage than good, and will hurt the value. If it were possible to undo the damage, our cars would never rust, iron pipes wouldn't pit, and everything would be made of steel. Don't let it worry you, they're still worth having.
if you collect coins, you need to learn that they must never be cleaned. cleaning, while it might make them look pretty, ruins their value as a collectable. ask your coin dealer.
