For general degreasing we use Black Scorpion and Purple Power, but any water-based degreaser should do the trick. Our parts washer uses specific parts washer fluid that is a petroleum-based industrial strength solvent. The fluid is similar to mineral spirits, which is also a good general solvent to use. It is very important that you use nitrile gloves in the parts washer and replace them if they tear, as solvents will cause chemical burns. For the ultrasonic cleaner there are a number of different solutions that will work, but we've had good luck with water, vinegar, dish soap, and salt.