To clean really nasty parts?
My method usually includes Mean Green(Simple Green knock-off), a steel wire brush, a brass wire brush, a nylon brush, and lots and lots of elbow grease.
I would have given my left nut for an ultrasonic parts cleaner today.
Today I had quite a few parts, way nastier than I'm used to cleaning, and it took me forever. So what do you guys use to clean your parts?