Find out if your bowling ball is still under warranty. If it is, the company will likely either replace the ball or fix it for you at no cost.
Fill the crack with the clear patch filler from the repair kit. Spray the patch with the kit's accelerator to speed the drying process. For small cosmetic scrapes, you can skip this step.
Sand the entire surface of the ball once the patch is dry. Spray the ball with water while sanding, or you can place the ball in a spinner that sprays water. Use low grit sandpaper if you want your ball to have more of a hook and arc, or use a higher grit sandpaper for more snap and skip. For the most consistent play, cross-sand at a 90-degree angle to the original sanding.
Polish the ball either by hand or using a spinner. Using the polish and polishing pad, rub the polish on every side of the ball for a consistent shine.