I've got a fan and clutch that was original (as far as I know) to a 67 440 GTX that I want to use om my 470. The clutch is not loose and turns properly but the aluminum part is grimy and the front face has surface discoloration (sort of rusty in color but there is no actual scaly rust) so I need to clean it. Short of degreasing and then media blasting, is there a better way to clean it (some sort of cleaner/solvent) that will not damage it and leave an original looking finish?