Step 4 · Scrape Away Softened Putty
While the putty is still warm and soft from the heat, immediately resume scraping with your plastic putty knife. It should now come off much more easily in larger, gummy pieces. For any extremely stubborn, thin layers, you may carefully use the edge of a utility knife blade. Hold the blade at a very low angle (almost flat) against the porcelain and use a shaving motion to lift the residue. Reheat the putty as needed if it begins to harden again.