I have just started in the windshield repair business and have been practicing on a practice shield. I have a question about the pit resin and the polish. I am following Delta's instructions and leaving a hump of pit resin, curing, scraping and polishing. After polishing I can still see a small amount of the pit resin. Is this normal? The repair appears to be complete but I can still see the pit resin spot. Should I be polishing more or doing something different with the pit resin? Please help.