Andy You can either use a spray on gasket remover which can be found at any auto parts store or isopropyl (rubbing) alcohol on a cloth will also lift the silicone residue it works great cleaning up uncured silicone. note: you may want to have a hose type vaccuum on hand to get any bits of silicone that may fall into the top of the heads. As long as you don't have any major gouges in the mating sufaces you shouldn't have any problems with resealing them using the paper gasket. Eastwood makes a special aerosol spray paint just for aluminum castings it will make your valve covers look better than new and won't flake off later. Ask Dave Swingle more about it. His son Gary used it on his BMW intake manifold. I was amazed how nice it looked. Dennis 5180 Duluth,MN