Put the lap in the freezer for an hour or two. Then take a wide blade scrapper (a razor type is best) and scrape it off. It sheds pretty quickly and if you do the whole thing inside a large plastic garbage bag the mess is localized. You COULD use the pitch again, as the chances of the material causing the scratch to be at the very top is pretty low. Your call. I have reused pitch several times over with no problems.