Water in the ultrasonic cleaner. Throw the parts in a ziplock bag with simple green or your preferred cleaner/degreaser ( try to remove as much of the air that you can). Throw the bag in the water in the Ultrasonic. That way you never have to clean the ultrasonic cleaner.

OK - an update. I picked up a gallon of Simple Green Pro Heavy Duty (purple color) and dropped the headset of my 1987 Centurion Ironman (Miami Vice) into a Ziploc bag as suggested. Because the headset was caked with hardened grease, I did a bit of scraping and cleaning before hand. I used a 3/1 solution (water/SG), set the unit to 150 degrees for 30 minutes, and let it ride. Worked really well - totally cleaned the headset, and the machine stayed clean and grime-free. The parts are cleaner than I could have gotten them by hand. Thanks for the suggestions everyone!

https://cimg7.ibsrv.net/gimg/bikefor...3a60dbc09b.jpg

I use citrus degreaser in a Ziploc bag with chain, components etc. Heat to 45*C and blast for 3 x 3 mins. It’s so clean you could eat your dinner off it when it comes out.

Also found out the hard way it removes anodising though :mad:

I used citrus cleaner years ago until I learned (the hard way) that it is hell on plastic and rubber.
I had to uninstall/reinstall my garbage disposal to replace the rubber collar.:mad:

How much degreaser do you add to the water?

I have used dilute Simple Green for years. I usually only use it on my chain, but is does a great job.

As I mentioned, I used a small Ziploc bag with a solution of one part Simple Green and three parts hot water. I filled the bag about 3/4 full and squeezed out the air. Then I dropped that into the ultrasonic cleaner for 30 minutes at 150 degrees Fahrenheit. When I was done, I just set the solution aside to settle and emptied the machine - no cleaning up! I’ll do the bottom bracket like this next.

I haven't bought an ultrasonic cleaner. What I do is fill a square large mouth plastic peanut jar with a couple inches of paint thinner , throw in the small parts, then shake it for a couple minutes. Then I put it in the kitchen sink( with a strainer in the drain for safety), squirt some dawn dish soap on it, and scrub with a tooth brush. After everything is clean I will squirt a little wd40 on everything and then put in plastic bag till I need it. so far this has worked for me

When I am cleaning parts in my ultrasonic cleaner, I use water in the tank and use jars holding the parts and the various cleaning solutions.