Remove any loose pieces of wood with a utility knife. Gently cut out pieces of loose wood with the knife. The repair will be more successful if the filler has solid wood to bond with.
Scoop some filler onto the end of a putty knife and spread it into the damaged area. Smooth the filler into the area so it completely fills it but is flush with the surface of the rest of the wood. Let the filler dry according to the directions on the can.
Sand the filled area with 200-grit sandpaper. Lightly rub the sandpaper over the area to remove any ridges or bumps in the filler.
Paint or stain the area using a color that matches the rest of the wood.