REMOVING STAINS OR SMUT MARKS Smoke stains on plastered walls are often a source of great annoyance to the painter, since they will come through and stain paint or wall paper, and are well-nigh impossible to cure. A method that is recommended for cleaning a smoky ceiling that is to be calcimined is first to brush the ceiling thoroughly, and then wash it with a strong solution of pearlash and imme diately rinse thoroughly with warm water. When this is dry, the ceiling should be given a thin coat of freshly slaked lime, to which a fair portion of alum dissolved in hot water should be added. When this is hard, a coat of glue size— or, better, a thin varnish size made by thinning a good grade of hard oil finish with turpentine— should be given before the water color is applied.
A class of stains that require radical meas ures to cure are those caused by smoky or smutty bricks, and laths containing bark. The only remedy for these stains is to ctrt out the plaster and remove the brick or the lath. These
stains will come through shellac or any similar coating that may be applied.
There are several methods of removing stains from wood or bleaching it, if the floors have not been varnished and the stain is in the wood itself and not on the varnish. Probably the most ef fective bleacher for taking stains of all kinds out of wood is oxalic acid dissolved in hot water, about one pound to the gallon. Vinegar or acetic acid may be added for particularly bad stains. This solution may be applied hot and must be allowed to become thoroughly dry be fore the wood is varnished or otherwise finished. Oxalic acid will take out weather stains and similar discolorations. Sometimes more than one application is necessary. It is best to wash the oxalic acid off the surface with clean water, after it has become thoroughly dry, or to treat it with vinegar or acetic acid.