Want to know a little trick for copper ? After you rock tumble then use walnut shells for an hour, the bronze coloured walnut oils permeate the copper and give a lovely sheen. cool toy have fun
they are pretty good for very crusty stuff. another type for cleaning more delicate stuff is a vibrating cleaner same as is used for cleaning bullets casings 👍
I've had the same tumbler for about 2 years now, they do a good job at cleaning, I also use small stainless steel balls and then use crushed maize polishing compound with a fine polishing paste. Only down side is that the drive belts are pretty poor quality and snap.