Hey you’re right. I just tried to find the post too but found nothing. I’ll try to find that post tonight.
I would recommend using a commercial ultrasonic solution though.
If I remember correctly your interest is in watches. I’m assuming that you purchased a jewelry cleaner type ultrasonic. In case you don’t already know, here are a few tips on using your ultrasonic that might help. First fill the sonic about 3/4 full with water and a couple of drops of bleach. You can put your cleaning and rinse solution in separate baby food type jars or beakers. The thinner the better. Your parts can then be put directly into the cleaning solution jar or better still placed in little baskets first and then placed into the jar. Baskets can be purchased at watch material houses. The jars can then be placed into the ultrasonic tank one after the other without having to change the tank solution each time. The ultrasonic waves will pass right through the glass jar resulting in cavitation of the solution. It’s a good idea to get the jars up off of the bottom of the ultrasonic by putting a spacer of some kind under the jar.
I’ll see if I can dig that post up and will add it to your thread.