Ya,x2 on the cover.
You just have a lot of grime on the engine....
Take a damp terry cloth(not dripping),and start wipeing down EVERYTHING with a mild solution(simple green works great),.....wires,firewall,get that stuff off the overflow tank,hoses,brake booster,MC,fender walls,ect.....
Once all that stuff is grime free,go over all the black parts,hoses,vac lines,wires,cowl shroud,ect...with some vinyl protectant and a lint free cloth.
Wax the inside of the engine bay,even if it is just to remove the oxidation,and then do the hood too.
A detailing brush help a lot,along with aresol window cleaner for gettin all the grime out of the nooks and cranny's......count on this taking a minimum of 2-3 hours if you plan on doing it right.