carb cleaner works good for alloy and shabbernigdo's right keep it off the rubber or plastic.i live in cali so i don't know if you guys ever heard of it, but there is this degreaser i use called LA's awsome, and i gotta say with lite scrubbing with an old toothbrush it will cut through bake on engine oil and pretty much anything i've thrown at it.

and it safe for plastic ,rubber , aluminum. also steel with quick rinse after scrubbing and heat dry.