After playing around with this for a few days, there is no denying that wet tumbling is THE best way to clean brass. Besides the stainless steel pins, I have also been playing around with ceramic media. The media I'm using are little 1mm balls. The ceramic media does a slightly better job of getting a very shiny luster on the brass, but it doesn't clean out the primer pockets quite as well as the pins, and it's a real pain to handle. The balls don't come out of the shells as easy as the pins, and they get all over the place. And you can't pick them up with a magnet like you can with the pins.
As far as the Thumblers Tumbler, I'm a little disappointed in it. After making these things for decades, you think they'd make a few small modifications to make it better. Mainly in the base. The drum itself is very well built. But the cheesy motor mount, shaft "bearings", and flimsy frame could benefit from a slight redesign. Maybe someday I'll make my own base. But apparently these tumblers last for many years the way they are, so it's probably fine. There's a lot of vibration in the system, and the thing squealed like crazy after the first 2 hours of operation. The squeal came from friction between the axles and the plastic "bearings". I put some plastic safe lubricant on them and that has taken care of that so far.
So here are a couple before/after pics of some dirty 460 brass I cleaned with the ceramic media. The cases are so dirty because these were wimpy loads that I made using Trail Boss powder. Since they are very low pressure, the brass doesn't seal up in the chambers and you get a lot of blow by.
It's a great system that I highly recommend if you are in the market for a new tumbler, or if you have brass envy. It's not cheap, but the consumables are cheap(water, dish soap, and Lemi Shine), so once you have the setup, it's cheap to operate. And it's clean. No more vibrating bowl dust all over the place.
