Last year I bought myself a stainless steel media tumbler from these guys: http://www.stainlesstumblingmedia.com/
Funny thing is the company I bought the tumbler from is in Utah, but the tumbler is made in Auburn, just a few miles from where I live....
Anyway, I decided to make a post about how this stuff works.
The pins are tiny, two or three would fit in a primer flash hole (and sometimes get stuck there)
So to demonstrate how well these work, I will start with some really ugly brass. I found this stuff in an old shooting pit (not used for the last year or so). I picked up about 10 lbs of brass, most of it I could use, a few odd ball calibers, but mostly 9mm, 45 ACP, 38 Spl, and quite a few 40 S&W (which I do not reload).
This is a pic of the 40 S&W brass after I rinsed the mud off of them.
Next I will rinse in hot water and put them in the tumbler
After one 6-hour cycle in the tumbler this is what the water looked like
This is what the brass looked like, I will try another round in the tumbler
After another 6 hours in the tumbler we have success:
here are a couple of before and after pictures to show the difference