For close- grained woods it is not absolutely necessary to use a filler, but since this aids in filling the pores, it gives an added hard foundation for the finish and makes for an even color.
If the floor be an old one, it is not too difficult a matter for even the amateur to render it fresh and attractive. In refinishing such a floor, all tacks should be pulled out, all nail holes puttied up, and all nails that must remain be driven below the surface with a nail set. The floor should be made as level, tight, smooth, and clean as possible. This may require much patient use of the plane and even more sandpapering. All the old dirt, discolorations, stains, shellac, and wax must be removed. Sometimes a thorough scrubbing with warm water and soap will do this, the floor then being rinsed with clear water and thoroughly dried. (Water must, however, be used sparingly and carefully, as it raises the grain of the wood and will, if too much be used, eventually cause splintering.) When the floor is perfectly dry, any uneven places should be sandpapered down. A solution of oxalic acid (made by dissolving one teaspoonful of oxalic crystals in one cup of warm water), if left overnight on stubborn stains, will often bleach them, the acid being, of course, thoroughly washed off and the floor dried. Old coats of stain and varnish may be removed by use of a paint and varnish remover, reliable brands of this being on sale at any paint store. When all these agents have made the floor clean, it should be gone over again to find any places where the grain may have been raised a trifle. After these have been sandpapered (a fine paper being used) and the floor wiped free from dust, it is ready for the new finish. All this time and care given to such preparation may seem unnecessary, but the results will justify it.
If the floor is to be stained, apply the stain to the bare wood, remembering that soft woods absorb more stain than hard varieties, and that the colors will therefore be darker. Marked grains in woods also produce a different effect than if the wood shows no grain, as stains penetrate less deeply into the grains and marking than they do in the open and more spongy parts of the wood.
When varnishing a floor, the room must not be damp, dusty, cold, or draughty. Varnish needs a warm, dry, and clean atmosphere. When any varnished floor begins to show wear in spots, sandpaper it lightly all over and put on a fresh coat of varnish. If kept well waxed, however, the varnish will not wear.