I follow this AI generated protocol on my low speed polishing wheel and it works fine:
For cleaning and polishing vulcanite (also known as ebonite) pipe stems, it's common to use a multi-step process with different polishing compounds. Red rouge is often used first to remove oxidation and minor imperfections, followed by white diamond compound for finer polishing, and finally, a wax like carnauba wax for protection and shine. This multi-step approach helps restore the stem's original luster and prevent future oxidation.
I also mix in some 600 grit sandpaper when necessary and “wet” sand.