I've heard Pine Sol is the go to cleaner for engine parts. Haven't tried it, but I've seen pics and things come out gleaming.
Easy Off oven cleaner in the yellow can - Place in the sun to warm up the part then spray Wait twenty minutes or so and either re-coat or rinse with water
Murphy oil soap, that's to clean wooden floors, not much degreasing power. I king of object to some of the above suggestions, Caustic Lye products such as hot tanks or oven cleaners, really bad for aluminium. But I can be patient and don't have a problem picking at stuff for a long time. Go buy some Castrol engine cleaner/degreaser at CT.
if petro products don't work try paint stripper... it has methyl chloride which one of the really good cleaners we used to have in the old days, but bear in mind there are reasons it isn't used for that anymore... like it's pretty evil on your body. I brush it on and cover it with plastic sheet to keep it from evaporating if you buy "gasket remover" in a spray can thats all it is... paint stripper Easyoff is ok on stainless steel but be careful on aluminum... it can eat alloy
Spray wand at the car-wash, hot soapy water. Have WD-40 WITH YOU to stop the IMMEDIATE rusting on the steel bits.
Vote for car wash, use lots of rinse. You are in BC so it is cold, keep case from freezing until you blow out well. When home blow out all passages real well. Bake in oven if at all possible at 225 for an hour minimum to dry all parts. Alternate put some place warm like near your wood stove or over a heat vent. Rod
Machine shops/rebuilders do hot tank iron blocks and heads in a mixture of water and caustic soda. Caustic soda is lye and it quickly eats aluminum. They have solvent tanks for aluminum. A million years ago you could buy a similar solvent product called Hydro Seal. It would clean baked on grease and take carbon off pistons and aluminum heads with an overnight soak. I used it on a Corvair rebuild (nothing but aluminum!) Hydo Seal is gone now (another toxicity victim), and replaced with Hydro Seal II, which the Internets seem to say is a disappointment, although I haven't tried it myself.
If you just want to drink a bunch of beer while you wait on the parts to get clean - use Dawn soap or a combination of Lemon Fresh Joy, Bleach and warm water!! If you dont have time to waste see above post
They make special bake ovens. They also make some really heavy duty dishwashers. And some high wattage ultrasonics are very popular. There is no single solution. Link http://www.enginebuildermag.com/Item/5218/cylinder_head_cleaning.aspx?MostRead=1 Rod
I used Pine Sol on some carbs I was rebuilding. Did an outstanding job. Definitely my cleaner for smaller parts.