Nail heads visible in hardwood flooring -- sometimes referred to as "shiners" -- can impact the uniform, attractive appearance of a floor. Where nail heads actually emerge above the floor surface, they can cause painful scratches or cuts and create a tripping hazard. Fortunately, covering nail heads in a hardwood floor is a fairly simple and quick project, depending upon the size of the floor and the number of nail heads that need covering.
Hold the tapered tip of a nail set that matches the size of the nail head against the nail head. Gently tap the other end of the nail set with a hammer, sometimes several times, until the nail head is about 1/8 inch below the surface of the flooring.
Clean the nail hole you are filling and a small area of floor around it if it is full of dust or other debris, using a slightly damp cloth. Let the area dry completely.
Squeeze or putty a small amount of wood filler into the nail hole. Use a wood filler that matches the surrounding hardwood floor color or a plain filler that you will color later. Use a putty knife to force the wood filler into the hole. Gently scrape off any excess wood filler so it is nearly or completely flush with the surrounding floor.
Wipe away any excess or dripped wood filler from around the nail hole before it dries, using a damp, clean cloth. It is OK if the filler rises slightly above the surrounding floor surface as you will sand it later. Allow the wood filler to harden completely.
Sand the wood filler gently, using a piece of fine-grit sandpaper. Run the sandpaper over the wooden floor in the direction of the woodgrain. Focus your efforts on the filler covering the nail head to avoid scraping the surrounding hardwood excessively, harming its finish.
Apply wood restorer to a clean, soft cloth. Rub the cloth over the dry, sanded filler until it matches the surrounding floor, if you did not use a filler that was colored to match the wood floor.