I have been using Lizard Litter (yea that's right it's called Lizard Litter) bought at my local pet store to clean and polish my brass in a vibrator tumbler. It is dust free and inexpensive. In the bag I bought for $10.00, I got 3 one gal milk jugs full. There is two types, the smaller size won't stick in the primer hole. I use the recommended amount of Dillon rapid polish 290, any of the commercial equivilent will work. The brass comes out clean and shinny.
I haven't found any down side and been using it for about 2 years.