Found this little gem. Gonna try it after the monsoon season.
Start engine, get it warm, not hot, just nice and warm. As an example if the car was fully cooled, run it for 5-8 minutes. Turn off engine.
Cover the alternator and air filter on your intake, Aluminum foil works great since the motor is warm. Everything else can be subject to light rinsing type spray, including the covered fuse panel. All of these areas get hit by water when driven in the rain.
Lightly spray entire engine bay with water from hose, you will see some light steaming, this is good.
Spray the entire engine bay, including firewall, plastic parts, metal parts, loom, coils and hoses with Simple Green. Set the hood down, not fully closed, just to it's safety catch point, and go find something else to do for 15 to 20 minutes. Let the simple green do it's work. Closing the hood let's the simple green interact with the steam you created with the warm motor. This loosens the tough stuff up so you don't have to work so hard in those heavily soiled areas.
Open hood, look for heavily soiled areas, wipe them with a rag, use more simple green if necessary. Rinse lightly with hose.
Spray entire engine bay with F-21, it foams, coat everything just like the simple green coating you did.
Close hood again, walk away for 10-20 minutes or until nearly all the foam has dissipated.
Open hood, Wipe up any areas that water settled and such. Wipe up any areas that the F-21 didn't dissipate on it's own.
You will note that the F-21 restores the black plastic parts to the same oem flat black color they were when new.. It leaves the paint shiney with no streaks on the fenders and fire wall. Best of all, it is not greasey to the touch.