REPAIRING ANY HOLES
Holes in hardwood floors can be filled with wood putty, but trying to apply wood putty directly over sealant or varnish is a bad idea. Just as buffing your nails helps nail polish stick, you need to rough up your wood floor so that the putty sticks. Always start with a rough-grit sandpaper (the thicker the varnish, the rougher the grit) and move up to finer grits. Also make sure to match the color of your putty to the color of your floor (oak, cherry etc).
How to repair a hole:
1. Take a little sandpaper in your hand and rough up the area around the hole. Start with a rougher grit sand paper (65 grit) to remove any varnish, and go to a finer grit as you need a smoother finish (to 150 grit, for example). Always sand with the grain.
2. With a putty knife or scraper tool, add wood putty to the sanded repair area, scrape flat and let dry according to the manufacturer’s recommendations.
3. Once dry, sand the putty in the direction of the grain of the wood. If the dried putty has significantly contracted or shrunk, you may need to repeat the process with another coat of wood filler.
4. Apply the finish, trying to match the varnish or poly urethane, or whatever it had on it, to the rest of wood.