It depends on the size of the damage. If the crack is not missing any material you can clean it with a small brush and lacquer thinner. Then squirt in some crazy glue and apply pressure to the crack until it closes. You should use about 60 mic to clean up the glue and a green scotchbrite under a orbital sander should bring it back to a matte finish. If the crack has material missing then you will need the repair piece that was left during the original install. You will have to drill out the damage and make a plug to fit, with a small negative angle and then you can glue the plug in using crazy glue but you may have to use a router to remove enough plug material so that you can sand it even with the deck. If you do not have a color matched repair piece you can still do the repair but the plug may be visable because of the color match.
Steve Reznick, March 2006