what do you use in the ultra sonic cleaner?
In mine, I usually just use water with a little Dawn dish soap as a surfactant and degreaser. It's usually not a good idea to fill an ultrasonic cleaner full of solvents; US cleaners do their job with cavitation and not so much the solvent action of whatever you put in there. For smaller parts, you can put solvents in a glass jar and then put that in the water - works the same and the solvents are contained. I don't clean everything in there; usually just the polymer frame, then clean the barrel with whatever potion I have handy. I flush out the water with Gun Scrubber and then CLP. There's something oddly satifsfying when you turn on the cleaner and see this brown cloud of crud coming out of the parts.