I have posted this before and this is what I do to every car or truck I have ever owned. Go to Walmart and buy 1-2 spray bottles of either Castrol super clean or the equivalent Walmart degreaser in a purple bottle, not the purple power crap as it doesn't work as well. Then buy a spray bottle of the cheap tire shine that is usually labeled 2000 or something like that it's usually in a lime green bottle. Get the spray bottle stuff not the aerosol cans as it works better.
Now got to your local spray off car wash and pop the hood and spray the entire engine compartment with the purple bottle degreaser. Be careful not to go crazy around the fan,pully or alternator bearing as you do not want to wash out the bearing grease. Let it sit no more than a few minutes and rinse with the high pressure rinse making sure it is all off along with all the the grime. Once that is complete, take the tire shine stuff and spray the entire engine compartment and close the hood.
Then Proceed to wash the rest of your car, BTW anytime you use one of these spray off car washes ALWAYS spray the brush out to get the sand and grit out from hillbilly bobs 4 wheeler before you start!
Go home and the next day pop your hood and all of your stickers, labels and everything will look brand new without any dirt or grime and will be nice and shiny. Just like the day it rolled off the assembly line!
GOOD LUCK!