Mildly OT (OP was talking about brass cleaning and I'm going to address cleaning an entire revolver) but I'm something of a believer in ultrasonic cleaning for jobs I just don't want. My sister carries a J-frame in the waistband of her clothes via a DeSantis ClipGrip. The revolver is completely unprotected against her bare skin. After a while, the build-up of dead skin cells in every crack and crevice is grotesque. Yes, I could clean and have done so before it but it's a pain in the posterior.
I dropped it off at a local shop that advertises ultrasonic whole-gun cleaning. I was responsible for cleaning the grip panels (no big deal) but the rest of the revolver looked like stuff was growing out of it and I just didn't want to bother.
It took 'em about an hour, but they returned to me a spotless pistol, properly lubed, that looked as good as the day it was bought. It cost me 40 bucks and, in practical terms, no time since I was on the shooting range the whole time and they told me that if I didn't already have a membership, they would have thrown in a free range pass just to thank me for having the work done.
Count me as a believer in the virtues of sonic cleaners.