Scotch-Brite may have some usefulness in the engine shop, but one place it should NEVER be used is on aluminum cylinder head deck surfaces. Using Scotch-Brite is the equivalent of strapping a chain to the cylinder head, having a buddy stand on it and dragging it behind a car on the street. Your results will be about the same – not flat.
Danny Soliz of Hill Country Performance Machine shows you why Scotch-Brite should be kicked to the curb.