I use a Chinese ultrasound set the temp to 30C. I use OMS which I guess is naptha, then paint thinner, then denatured alcohol. About 10 min each. Comes out squeaky clean. Then throw it in my wax crock pot at 190-200F. Got this from the friction facts / ceramic speed guy.
The ultrsound is also good for general cleaning using OMS.
scott s.
.