What I do is to get a can or 2 of Gunk spray engine cleaner and a bunch of
quarters. I drive over to the do-it-yourself car wash and spray down the
grungiest parts, sometimes going over them twice if they are really bad.
Let it sit for 10 minutes or so.
Then put in the quarters and select the strongest detergent the machine
has. (some say "engine cleaner") Wash off the gunk and grease, then go
back with the clear water rinse and wash off the detergent. As soon as
you are done, start your engine and let it run until at least the parts that
get hot are dry. It may take several washer cycles to finish everything.

Before doing this you may wish to put a plastic bag over certain electronic
parts. I haven't had much of a problem with this because most of my
electronic parts don't get that slimy. Good plug wires do OK but old ones
will give you heartburn until they are really dry.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma