Clean the surface thoroughly. Vacuum and then clean the affected area with the leather cleaner. Make sure it dries completely, either with a hair dryer or a towel, or simply let it air dry.
Sand down the area with 600 grit sandpaper. This will remove any flakes and other imperfections around the affected area.
Gently wipe the area with rubbing alcohol and allow it to dry completely, again using a hair dryer, a towel or plenty of time.
Match the repair kit dye colors to match the shade of the leather or vinyl. Most leather repair kits come with a number of colors to mix together and recreate the correct shade.
Apply the repair solution to the area as directed. This is usually with a sponge or airbrush. Let it dry for several minutes, then wipe it with a towel. The color will remain in the worn area, and will easily wipe off the portions of leather or vinyl that are still good.
Allow it to dry overnight and apply a conditioning product the next day.