What the ultrasonic cleaners really work well on is cap and ball cylinders. I give them 2 or 3 cycles in Dawn/H2O, remove them and dry with compressed air. I then remove the nipples, do a little touchup with a nylon brush and reinstall the nipples with a little anti-seize, actually choke tube lube. A little Ballistol wipe down on the cylinder inside and out, and GTG. Removing the nipples each time is probably overkill, but I don't like stuck nipples.
B. N. Scotty