And a couple videos I've seen guys using these fiberglass pen brushes to scratch away numbering with really good results. I bought one and used it myself but it turned out like dog crap. The letters look like they had been scratched in the areas around the lettering that got scratched changed color. I tried changing my technique and not running so hard but no luck. Anyone try these? Maybe the one I have is too course. Are they all the same? What brand or people using?