I don't have a hot tank or parts washer. I'd like to get most of the carbon and oil out the the plenum, runners and manifold. Purple stuff is supposedly bad for aluminum, so I tried soaking the runners in dish soap and water - I guess dish soap also is bad for aluminum because they look awful. So, how do I clean everything out with hurting the aluminum?

get something like a dremel with a sanding drum and knock it off that way, while your at it, smooth out all the casting marks.

Just soak it in warm soapy water overnight, then use a wirebrush and carb cleaner or similar to scrub as much as you can out.

You can clean up the runners with a little steel wool (#00).

I used a chemical solvent made by Castrol. I don't remember what the name was, but it came in a purple bottle. I think it was called Super Clean, and be careful when using it with aluminum.

Super clean is great stuff, and yea it can etch aluminum if you dont pay attention

I used carb cleaner, mag cleaner, and a bottle brush. Inside and out they looked good.

I have read that oven cleaner works well. I have also used brake cleaner for short bouts and had good results.

I've used castrol super clean, brake cleaner, some green stuff. Soaking does wonders, but that crap really builds up. I think Ed Maher had a pic of his runners sitting in a dish washer, you could try that.