Lovvve my tumbler, it’s Thumbler Tumbler. You can get one for under $100,it works fantastic. Tumbling(burnishing) not only makes your metal shine, it also hardens it, I think the hardening of each piece is a even better benefit than the beautiful shine you get. I usually tumble for 2hrs, unless it is a stone with mohs hardness of less than 6. Like Sylvia said, no pearls….though I have had luck tumbling shell pearls.
When I make Zircon and Swarovski pieces, I even let them go for 3hrs, they come out amazing and very sturdy....especially important for my prong rings. The AB has never come off for me either….which I have heard it does, just depends on the brand tumbler you buy I guess. They are all different.
I use the same barrel for my copper and silver, never had any trouble from it, I always rinse it out good after I tumble copper though.
I have also use it remove tarnish, I spiff up my personal earring collection prob. once a year like this. I just toss them in the tumbler for about 20min and they come good as new. I usually give items that have been sitting for a while a tumble right before I ship them to give them an extra nice shine too. The trick is to use extra Dawn to really lubricate the shot when you are doing a "tarnish tumble".
Just don't get any bright ideas to shine up your wedding ring....it will dull your diamonds, can’t tell u why, but it does..Learned the hard way =/
Here are a couple of Wire Geek threads that might be helpful too…..
http://www.etsy.com/teams/10722/wire-geeks/discuss/9089420/http://www.etsy.com/teams/10722/wire-geeks/discuss/9155324/Good Luck to u, yessss, buy yourself a tumbler,it's my best tool ;)!