Wipe the surface of the scratch with a damp cloth to remove dirt and dust so that you can see how deep it is.
Look closely at the hardwood surface to determine in which direction the wood grain runs. The wood grains look like tiny, thin lines that run in a single direction along the entire length of the hardwood board.
Fold a piece of 200-grit sandpaper into a square and wrap it around your finger so that only a small portion of the sandpaper touches the floor.
Rub the sandpaper only over the scratched area of the hardwood, making sure to move it in the same direction as the grain of the wood you identified. Continue sanding for five or six strokes.
Wipe the area with the damp cloth and see if the scratch has been removed. If slight traces of the scratch still remain, switch to a 300- or 400-grit sandpaper and repeat the sanding process. The higher-numbered sandpaper is finer and will polish the surface to remove the remaining scratch.
Wipe the hardwood again with the cloth to remove all sanding dust.