Tried the tumbling, found that even with care I had a lot of the corn cob media all over the place. And I didn't like now long it took or the fact that on the deeper .38Spl that it hardly cleaned the insides at all.
Bought an ultrasonic cleaner and found the heaven's opened and angels sang ! Yes I need to set the brass aside for a few days to dry. But I find it's far easier to use and faster to do a big batch of brass. And best of all any spills are easily wiped up or if I miss them are polite enough to go away by themselves. The insides of .38Spl are not pristine but they are darkish brass coloured. And that's a heap better than sooty black which the vibrator and corn cob with polishing cream did.
Stainless pin media is better by seen in the evidence of many videos. But then I'm back to separating pins out. And it's simply so much easier to just rinse, dump, spread out and then get Mother Nature to dry that for me US only is the best way and the easiest way.