I reloaded ammo years ago and still have the tumbler some where.it viberates and uses corncob Medea.i will try this monday on the coins i found Saturday.it will make old gun cases look like new.Scott
I have a large tumbler that I use for casings as well. Add some powdered jewelers rouge to either corn cob, walnut, or rice tumbling media. Works great with coins. I don't know if the vibrator type will give enough aggitation, or it just may take longer.
I really don't think the vibrating kind will do a good enough job... I use a rock tumbler and even tumble my silver rings I find in the water and they come out almost new looking.