I think the stuff Montague was referring to is "Demaon Clean", put out by Dave Gierke Flying Models.

You brush the stuff on, wait 30 to 40 minutes, then scrub the engine with a tooth brush under warm water. Works really well for that brown, baked on, oily residue.

Stuff is pretty nasty. You'd want to wear rubber gloves while working with the stuff. (He recommends it.) But I guess if it's going to work, it has to be potent.

Not sure if the price is still accurate, but I have an order form that came with mine. $18.95 (includes shipping) for an 8 ounce can.

Dave Gierke Flying Models
PO Box 83
Bowmansville, NY. 14026
716) 681-4840
(Assuming that's still accurate.)
Dennis-