I was planning on cleaning my car engine. What are those black dirt specs on the engine, and metal parts,mainly like on the distributor and the valve cover. I tried using engine degreasers, cleaners and scrubbing off the dirt marks, but they are really stubborn. My friend bought her car recently, and her engine is super clean. What did they use, or did they steam clean it? Where can I get a steam cleaner, or is there a different route..ho much does it usually cost?