I have an old retired crock pot that I put Ethylene Glycol anti-freeze in and set the temp to low. Drop the engine in and let it simmer for about 12 hours. When you take it out and rinse it off it will be clean as new. Here is a link that has some good info.

http://www.rcuniverse.com/forum/m_12...tm.htm#1207200

Good luck. [8D]