Spray full-strength Simple Green on your cold engine (try to avoid spraying the electrical sensors), then scrub with a regular toothbrush. If you take a chance and hose it off with water (I did, without any problems), use a regular garden hose without a nozzle. DON'T use a high-pressure wand at a car wash. Dry the engine with an old towel, then immediately drive the car for a good 20 minutes so the engine heat evaporates all the remaining water.