Ted, one can use a water base cleaning solution because it's safe and it works well in a ultrasonic cleaner. I've used it for decades. Usually, only a few hours will loosen the worst grime, then I brush off the loosened grime with a tooth brush. Then I rinse the item well under very hot tap water, heating the metal. I use compressed air to blow off and out all water while the metal is hot, then spray with WD 40 or similar and let it cool. Later, I blow off any extra WD 40 and wipe clean .
I am not sure if you are recommending one use kerosene, lacquer thinner , etc. in an ultrasonic cleaner. Sounds dangerous to me and then you have the problem of proper disposal.
