* To Use Paste Wood Filler *
Thin with paint thinner to the consistancy of heavy paint. Brush on, first with the grain, the against the grain. After the filler has dried (1/2 hour to two hours ... but not over night), the color will lighten and reel dry but not hard. [Wipe with burlap or rough cloth against the grain] - this is the step where you will need practice, and can be innovative with experiments. We sometimes use the edge of a razor blade or stiff cardboard. The purpose is to remove filler from high portion of wood surface, while allowing it to remain in the grain, or valleys, bringing both to an equal or near-equal level. Depending on how exact the piano finish is to be 1-3 coats may be applied.
Then stain if necessary, seal with one or more coats of thinned shellac, sanding lightly and tack-clothing between cats, then varnish. Rub out with pumice then rotten-stone to luster desired. Use wipe-on wax, and maintain with wax as needed.