engine cleaning
Lots of things can do that, many types of solvents can oxidize the outside layer of plastic and make it opaque white. It's the same reason (oxidation) that black plastic trim turns gray/white after a while in the sun, but it's oxidized from the sun and not solvents obviously.
Purple power and then rinse with the hose. I'm not too picky about the water, I rinse it while it's running. It seems to work better than the Gunk EngineBrite stuff to me, plus the Gunk Enginebrite odors give me a headache when the engine gets hot.
purple power is AMAZING at gunked on and old dirt. but it will remove paint too so make sure you dilute it... plus you dont go through quite as much.






