I clean with simple green diluted 4:1 or 10:1 depending on how nasty the engine bay is. Use a soft brush to scrub the heavy gunk off then rinse gently and dry. Dress the area with which ever you prefer from the Poorboys line NL, Bnb, or TR. I did an 03 X5 (pics of its swirls coming tonight) and used TR to dress and it looked great.