Re: Ultrasound Cleaner
I had the same thought, and contacted Brownell's about it. They said that the ultra-sonic cleaners will clean the brass down to bare metal, removing carbon, dirt, primer residue etc. but that it will not remove stains. In other words, the brass will be clean, just won't be bright with a polished look.
One other thing - don't use a cleaning medium with any ammonia in it.