Repair color damage
There are at least four methods of repairing color damage in finished wood. The first step is to determine which method works best. To do this, apply a liquid to the damage and see what happens.
The best liquid to use is mineral spirits. It won’t damage any finish, and it penetrates any wax that might be on the surface to give a more accurate diagnosis. Liquid from your mouth also works well, so I call this the “spit test.” When you dab any of these liquids, one of four things will happen:
1) The color comes back. That’s great, because the solution is merely to apply some finish.
2) The color only partially comes back. You’ll have to stain before putting on more finish.
3) The color doesn’t change. Stain won’t work. You’ll have to “paint” in the color with a colored marker or artist’s brush before applying finish.
4) The color gets too dark. The best fix is to apply clear paste wax, or seal the damage with a fast-drying finish such as shellac, then coat with the finish of your choice.