Chris,

My understanding from everything I researched on the net before buying one is the chemical reaction that occurs with various acidic solvents used breaks down the brass on a microscopic level when it's removing primer/powder residue.

I read that guys using dry(tumbler/rock washer with a medium) and wet(ultrasonic cleaner/bath solution) didn't notice any difference in case life from using either method.

I choose the ultrasonic cleaner as it's faster and quieter than a tumbler(apartment life so it's a factor for me).

I'm going to experiment myself to confirm the above from what I've read, I plan to primarily use the tumbler to remove lubricant after FL sizing.

I've also altered the mix in which I use from the 6mmbr 'recipe' or whatever you want to call it.

at 50 degrees
20min in vinegar 80:20 with tap water
10min in Birchwood casey case cleaner
sodium bicarbonate bath for a min
rinse with hot water
and then in the oven for 10-15min at 150degrees.

I can do 300 cases in less than an hour from start to finish. I love how spotless/shiny they are when they come out

Paul