Thanks it makes sense. I will give it a try in my ultrasonic cleaner with IPA and heater on ... I need to buy a gallon of 99% IPA somewhere... (fun fact if you google "IPA gallon" only beer shows up).
Do not do this!!
It’s not safe to fill a regular ultrasonic cleaner with flammable solvent. And it’s expensive.
Instead, fill the machine with water. Then place into the water a smaller container of solvent with the dirty item. The container can be open (like a tray or beaker) or a plastic bag. Plastic bags are a great way to massively reduce your solvent consumption, since you can put in your board and then just enough solvent that when zipped closed, the board is submerged. Seal a bit of air into the bag; this will keep the open end of the bag floating at the surface.