Apply paint stripper liberally to the wood surfaces of the piano using a paintbrush. Use a toothbrush to apply the paint stripper to the more intricate and hard-to-reach parts of the piano.
Remove the paint stripper using a putty knife to remove the previous worn finish. It is important to follow the grain of the wood while doing this, otherwise you may do permanent damage to the wood.
Use an alcohol-based paint thinner to remove the varnish from your piano. Apply this using steel wool, rubbing the wool against the wood to remove the varnish. Repeat this as many times as required to remove the varnish.
Wipe off the paint-thinning solution with paper towels once you are sure all the varnish has been removed.
Examine the bare surfaces for any repairs that may be required. For example, if there are any chips or cracks in the wood, now is the best time to repair them with an application of filler.
Apply a new finish to your piano. Use a spray gun to apply fresh paint or stain to any areas that visibly require it . Once dry, refinish the piano with a gloss tung oil, rubbing it gradually into the surface of the piano. This is more hardy and attractive than simple varnish.
Lightly rub your new surface with steel wool to remove any loose debris or dust that may still be present, but be careful not to scratch the surface.