Smooth a 1/4-inch thick layer of wood putty over the entire wood window frame using a small trowel. Scrape off the putty using the trowel also, as this will push the wood putty into the grooves and scratches, and take it away from areas where the putty is not needed.
Allow the wood putty to air dry in place for eight to 12 hours.
Spread wood stain over the entire wooden window frame using a sponge brush. Select any color of wood stain you prefer, and apply it in a thin layer. Apply additional layers of stain if you want the color to appear more saturated. Let the wood stain dry for eight to 12 hours.
Apply a medium layer of clear varnish over the entire wooden window frame using a 2-inch flat paintbrush. Select glossy varnish if you want the wood to look shiny, or choose matte if you want the wood to look more flat. As with the putty and stain, allow the varnish to dry for eight to 12 hours.