Get a few plastic bags or reynolds wrap and cover up the fuse box, intake (if you have a cone filter in the engine bay), alternator, distributor cap if you have one, and any other sensitive exposed electronics you see. Then spray with either an APC or degreaser and agitate until satisfied then rinse gently. You can dress with any plastic dressing of your choice for the most part but I prefer a cheap aerosol tire shine like the basic armor all. It's cheap and surprisingly lasts a long time.