theres this stuff in an aerosol can called "Inside Out". It works really well. You just wipe down your engine bay a little bit to get rid of some of the dirt and dust, and spray on the stuff. It shines up all of the rubber hoses and cleans off the valve cover and all the plastic stuff. I'm not sure how much it costs, but i think it comes in like a case with a few cans in it. A guy i work with had it and sprayed my engine for me. You can also use it on the inside of your ride too, like on the dash and stuff.