First I disassembled the top end and soaked it in the sink filled with hot water and "simple green" for a few hours. For the combustion chambers and ports I used oven cleaner and a brass brush; then I used the dremel tool with the scotch brite wheels. For the mating surfaces I scraped off the old gaskets with a razor blade, then cleaned the surface with simple green, scotch brite pads, brass wool and wiped them down with naptha. For the fins I used simple green and scotch brite pads. And a lot of patience and determination.