Some ask me how I keep my engine bay so clean.
I did this yesterday in preparation for the Woodward Dream Cruise next weekend

With a cool engine temperature I cover the alternator with plastic and simply lightly spray everywhere with a garden hose and rinse away dust.
Then uncover the alternator and go for a drive and let the engine heat dry everything completely.
Then simply detail with any product you choose to restore the black surfaces.
***I have NO oil leakage but if you do, spray oily area with Simple Green and allow about 10 minutes for it to penetrate areas applied before rinsing as I did here.
***Note: If you remove your OEM engine cover be sure to cover the throttle body (Air Inlet) completely with plastic !!