[b]OK, no crock pot and no desire to buy one just for cleaning the odd engine now and then.

If you have a hood over your cook stove with an exhaust fan - be sure it blows outside your house, many do not - you can use a pot on one of the burners. This will need careful monitoring for the first hours, you need to keep it around 200F, and not let it boil. An unscratched pyrex pot is best, with a lid. After use it can be cleaned and used for cooking again. Scratched? You shouldn't be using it anyway - the scratch is a weak spot. The lid? As the liquid vaporizes it will condense on the inside of the lid and drip back into the pot.

Or in the oven, if the thermostat works well at low temperatures. Still need the lid on the pot and the exhaust fan. Also, in the oven you can use a cookie sheet under a plastic pot with a snap on lid. A five quart ice cream bucket for example, or the tub you got your oleomargarine in for smaller engines and parts.

In all these cases, antifreeze (so far) is the solvent of choice.

If your wife has an ultrasonic jewelry cleaner, that works for parts small enough to fit inside. And so long as she will let you.

Back to the crock pot. It can be operated much more safely than directly heating the antifreeze. Using the same plastic oleo bucket I mentioned before put the parts and antifreeze inside and snap the lid on. Put this inside your crock pot and add water until it's near the top of your plastic bucket. When when you turn it on, it will heat the water, the heat will transfer through the plastic and heat the inside. The water vapor will still condense on the inside of the lid and drip back into the pot, on the plastic bucket itself you will see the top bulge as the air expands, but none of the glycol vapor will escape. And afterward the pot will still be safe for cooking.

Bill.