Coat the door with a second application of polyurethane to seal in the numbers and lines. Once the protective coat has dried (about 4 hours), lightly rub it with 220-grit sandpaper and wipe it clean, as in Step 1. Finish with a final coat of polyurethane, but let this one dry for a full day. Then buff it with 0000 steel wool. Once you wipe it clean, it will provide a slick surface for the pucks.