Make certain everything is as clean as possible before you start. Lacquer thinner will do a good job of de-greasing. The cast (rough) parts clean up well blasting with glass beads. As T.C. says, stay away form internals. The smooth parts need to be buffed and polished. If they are in rough shape to begin with, start with some 220 grit sandpaper working your way down to 600 grit, then buff. Buffing is a dirty, time consuming job. So is blasting, for that matter. Both are best done outdoors. Don't do either one with out proper protection. Eyes, ears and nose need to be covered. If you can find someone to do both reasonably, by all means do so.