I probably don't get the same results to the degree of the ultrasonic cleaner but it works pretty well. I use an old 1 Gal. plastic wide mouth jar put about two qts. of hot tap water and add two tablespoons of Lemishine and mix well,add cruddy brass make sure it's cover with the mix and let soak for an hour with a couple of shakes in between.
I then rinse well with clean water shake brass dry in an old pillow case and throw it in my tumble for about an hour or so that's loaded with cob media and cap full of NuFinish. It's not to high tech and I don't have to clean brass to that extent that often so it a cheap solution. You guys might want to try the Lemishine in you ultrasonics,it especially works great if your brass is tarnished. The tarnish will turn a light shade of pink but goes away when tumbled.
Before/old Mil-Surplus brass

After