Spots or stains of grease or oil are often found in books. They may be wholly removed by applying carbonate of magnesia on both sides of the leaf stained, backed by paper, and pressing with a hot iron, after which the sheets should be washed and left under pressure over night. Another method is to dilute spirits of salts with five times its bulk of water, then let the stained leaves lie in the liquid four minutes, after which they are to be washed. Still another method is to make a mixture of one pound of soap, half a pound of clay and two ounces of lime, dissolved in water to a proper consistency; apply it to the spots; fifteen minutes after, dip the leaf in a bath of warm water for half an hour, after which dry and press until smooth. Stains left by mud on the leaves of a book (a not uncommon fate of volumes falling in a wet street) can be removed thus: spread over the spots a jelly composed of white soap and water, letting it remain about half an hour. Then dip the leaf in clear water, and remove the soap with a fine sponge dipped in warm water; all the mud stains will disappear at the same time. To remove the last traces of the soap, dip a second time in clear water, place the leaf between two sheets of blotting paper, and dry slowly in a cool and shady place. The same process, of washing in soap and water, will remove what are doubtless the most common of all the soilings that library books undergo, namely, the soil that comes from the dirty hands and fingers of readers. It is sometimes necessary to color the sheets that have been washed white, so as to correspond in tint with the rest of the volume, which has not needed that treatment. An infusion of cheap tobacco leaves, or a bath of brown stout will effect this. In all these methods of removing soil from the pages of books, it is absolutely necessary to give attention to thorough washing after the chemicals are used. Otherwise there will remain an element of destruction which will sooner or later spoil the book, to restore which so much pains may have been expended. And one can readily learn how to restore a valuable book by these methods. He should, however, first practice on the restoration of a volume of little worth--and venture upon the treatment of a precious volume only after practice has made him an expert. To restore a fresher look to volumes whose bindings are much rubbed or "scuffed" as it is sometimes called, one may spread over their surface a little wet starch pretty thick, with a little alum added, applied with an old leather glove. With this the back of the book, and the sides and edges of the boards should be smartly rubbed, after which, with a fine rag rub off the thicker part of the starch, and the book will present a much brighter appearance, besides being rid of dust and soil.