Harbor Freight sells rock tumblers only way to go. with some aquarium rock, a drop of dish
soap your set. Do not clean the key coins though. Also depending on how much crud is on your
coins sometimes cleaning them will make them look worse.
White vinegar ...Put the pennies in a plastic drink container and fill past the pennies with straight white vinegar. Screw the cap on and shake shake shake. Leave sit overnight. Rinse with clean water until the water doesn't come out murky.
plehbah is the master of the dirty wheaty pennies. he will send you a divine revelation on how to clean them.
Seriously though, go to the cleaning and preservation section and read Don in SJ's post about the peroxide method. It works well, and it is titled "cleaning Large Cents"