i've sprayed mine off for years without any problems. All I use is the engine/tire cleaner at the car wash. Once a year I clean the whole engine bay with Simple Green.
I don't really cover up anything, I just use common sense. I don't spray the alternator directly or my CAI. Also I don't spray at full blast, I let the sprayer spray in idle mod so its more gentle. By doing this method i've always had a nice and tidy engine bay. The results speaks for themselves...
