I have an alternative to the antifreeze method:

1. Get (ask, beg, plead or... steal) a suitable cooking pot to immerse the engine into
2. Fill the pan with water and add 2 or 3 (two or three)tablespoons liquid dishwasher detergent, yes the one used for cleaning pots and pans (Palmolive is a good brand)
3. Bring mixture to a boil in a stove top, keep boiling for 3 - 5 minutes
4. Take pot out of fire and put engine in..... ( i just take teh muffler out and put the engine in seals and everytging)
5. Let it soak for about 20 min to 1 hour as you van handle it
6. Take engine out and clean with a stiff bristle brush (steel or brass ones I think)

VOILA!!! the gunk is gone.

The temperature of the mixture is below the temperature of an operating egine and the detergent is not as hard on o rings and plastic and you can afterwards clean the pot and return it to your significant other