[vettestr]

All great info and I second the Simple Green but stress the concentrate version. I buy the gallon jugs and put in a spray bottle with mist setting. Every car I own gets a spray down any time I open the hood to keep clean.
I have found it does not dull paint or hurt anything but do keep off mirror finishes or wipe off ASAP. The stuff just dries and keeps on working and does not smell bad as a big plus. If starting on a grimmy engine it takes a little more work. Go to a car wash with a pressure washer and get the big chunks off and start working on the buildup.