I don't know why I never thought about doing this before but, it worked. I had some nuts and bolts that needed cleaning from doing a clutch hydraulics repair on my 1972 Land Rover. So, I filled my tumbler with the parts, the pins, and soap and ran it for two and a half hours. The parts came out pretty clean. The pins couldn't clean down in the fine threads on some of the bolts but, the big spring in the picture was covered in rust. All the parts were oil covered or rusty.