While the ultrasonic cleaners do a great job get stuff clean, they do nothing for the oxidation, stains or the generally dull look that cases get with use, unless there's some magical solution that I'm not aware of.
A vibratory tumbler will polish them up nicely, but they won't be nearly as clean inside or in the primer pockets.
What is your priority? In truth, wiping them down with a rag is as clean as they actually really need to be. Anything more is for bonus points.
MSgt, USAF, Retired
NRA Life Member
The hardest thing to explain is the glaringly evident which everybody had decided not to see. - Ayn Rand