1. If the old coats are not worn off or chipped in spots, then thorough cleaning followed by sandpapering with No. 00 sandpaper will suffice.
2. If, however, the old coats are worn or chipped badly, then all the old coats should be removed before refinishing. This can be done a) Mechanically, by scraping with a sharp blade or by sandpapering, or b) Chemically, with a commercial paint, stain or varnish remover, or with a home-made remover, as follows: Add 2 tbsp. lye to 1 qt. warm starch solution (as for starching clothes). Apply with a vegetable fiber brush or cotton mop. Let stand several minutes or until the old coats are softened. Then scrape or rub off. Rinse well. Then bathe with a vinegar solution (3 parts vinegar to 1 part water) to prevent any of the lye remaining to damage the new coats of finish. Rinse well and dry thoroughly, then sandpaper smooth and wipe off dust before applying new coats.
1. When restaining old woodwork, cover the wood thoroughly with a paint and varnish remover, taking care to wash out as much of the old stain as possible. As there will be some stain remaining in the wood, this must be reckoned with in restaining. A wood previously stained in mahogany should be stained with mahogany again or in one of the darker browns. The spirit stains, because of their penetrating qualities, are the only stains which are effective for refinishing work. Woods previously stained green will be best finished in either green again or in a weathered oak. Previously finished woods in natural colors do not present these difficulties. Because the color of the wood may be darker and more yellow than the original wood - due to ageing - silver gray effects will not be as clean in tone as might be desired. After restaining, use the paste filler, then the shellac for a binder, varnish, and rub or dull the finish as for new wood.
2. Revarnishing. See A: To prepare old surfaces.
3. When rewaxing woodwork, use a commercial brightener or liquid wax, which cleans as well as polishes. Or turpentine or gasoline may be used before rewaxing.
4. To repaint or re-enamel. See A: To prepare old surfaces.