Depends on how large the part is. For small parts (assuming I'm removing them from the playfield) I use a vibratory tumbler w/ corn cob media, run for several hours. Nice because you can just set them in and run them over night. Larger parts like ball tracks, I use Novus 2. *I think we've discussed in previous posts?* I use Novus 2 on everything on the playfield then follow up w/ Meguires caranuba wax. Good luck and keep them pins running.