my method comes from trial and error, if you have a magnified look at the rubber after grinding it has lots of rubber parasitical,s still attached to the surface that do not want to rub off with abrasive paper etc. My solution as to make them more ridged so the abrasive will take them off. I found that a thin coating of French Polish well thinned or some fast drying cellulose Lacquer, this stiffens things up so 600 wet and dry will remove them and to get a good polish on the rubber 800 wet and dry followed by Solvol autosol polish.
