Step 1: Prep the damaged area
Dogs and cats still haven't figured out how to open doors, but that's never stopped them from trying. Painted doors can be spackled and repainted to hide the damage, but natural wood doors can be more of a problem. However, if the scratches aren't too deep, you can usually mask the damage with stain and varnish.
Sand the damaged area lightly (Photo 1), feathering the sanding into the surrounding undamaged area. Wipe off all dust.
Step 2: Apply a gel stain
If you don't have the original stain or finish, find a matching stain at a paint store. Gel stains (available at home centers and paint stores) work best. Buy a small piece of matching wood and experiment with it first, or bring a photo of the door to the paint store for help. Start with a lighter stain—it can always be darkened. You can also buy a few different colors and blend them or streak them together.
Wipe the scratched area with a rag dipped in thinner to keep the stain from looking blotchy. Put a small amount of the gel stain on a rag, then dab a little on a dry brush. Wipe excess stain on the rag. Drag the brush lightly along one edge and quickly wipe it dry to see how the color looks. Leave the stain on longer, apply additional coats or blend in other colors to darken it (Photo 2).
If the stained area looks too dull after it dries, lightly spray the area with clear finish, feathering it into the surrounding area.