Engine Cleaner... Man I hate caleche roads!
Dust is my enemy when it comes to keeping the engine clean. :cuss:
If you wanna do it right, don't go for the quick-clean sprays. I'm sure people have done it tons of other ways, but the quick clean always ended up slinging cleaner all over the engine compartment, and under the hood. You usually have to idle the engine while using this stuff, and the fan sends it everywhere.
Just get yourself a pile of rags, some "Castrol Purple Cleaner" or a similar de-greaser, and some water. I used to have a water hose set to just barely trickle, to rinse while I worked. Clean small sections at a time to prevent the cleaner from drying out. I have used small plastic brushes, sponges, tooth brushes, even canned compressed air.... you name it. You have to get creative in some areas. Just don't spray any water on the electrical connections, and you won't have to worry about it. When in doubt, just use a damp rag and wipe it off. Follow it up with a dry one, and there you go.
Once you get all the dirt, dust & grime off... use a protectant on the plastics and rubber. Something like Armor-All, or a good Vinyl and Rubber cleaner on all the plastic and Rubber hoses.
I've even gone so far as to use a "quick-detail wax" spray on the painted surfaces to help reduce water & junk from sticking in between cleaning.
Once you have spent an hour or two cleaning your engine, you'll be more inclined to keep it that way... and it will take less time each cleaning to get it purdy.
Hope this helps.