TBH I never bothered with an ultrasonic bath just cellulose thinners and an old toothbrush for intricate parts or an offcut of hardwood to dislodge stubborn build-ups -far more friendly on TCT items@imageel are you talking about in conjunction with an ultrasonic machine or just as you would usually do it?
I suspect that acetone maybe available at reasonable cost, I haven’t tried it out in plastic containment but suspect it won’t work well.