this is what i use(takes a lil time but results are amazing)
i use Honda spray and polish(pick it up from any motorcycle dealer for bout 7 bucks a can)
its a cleaner/degreaser/polish all in one.......comes in an aerosol can spray it on let it sit wipe it off and ur done looks like u just sprayed anything thats plastic with armor-all or tire foam and its safe on any surface....i used it on my wheels even my paint at the last car show i went to cuz i left my meguiars spray wax at home.....great stuff and no water requiredldtu: just a cotton towel and maybe some brushes for hard to reach spots in the engine bay