Hey Tom,
I can add a little something to your solution. And with this you don't really need the risky mechanical buffer. After you daub on the paste shoe polish, rub it into the scuff with the back of a spoon with moderate pressure. Smooth it out as dries\u2014still with the spoon.
Then buff it out with a regular shoe polishing cloth. This is best done with the saddle mounted on a bike and the bike on a stand. Hold the cloth by two diagonal corners and just saw back and forth just like the vintage shoeshine boys used to do. Popping the cloth isn't necessary unless you have rhythm and/or an audience. Actually if you can locate a vintage shoeshine boy, it's easier just have him do it. Comerica Bank in Palo Alto, California has a shoeshine guy, I don't know about their Detroit Headquarters.
Mark Fulton
Redwood City, California