Black Magic 2-IN-1 Engine Shine safely cleans, degreases and shines in one easy step. For best results, use on a warm engine that’s turned off. Spray over the entire engine, on fenders, cowlings and under the hood, wait 15 minutes and then rinse engine compartment using a light flow of water, using as little of water as possible. Do not spray water in air intake, on carburetor, or on exposed wiring. For tough stains and grease, use a brush or rag.