Ink-spots or mildew stains may be wholly removed, when freshly made, by
applying a solution of oxalic or citric acid, and then washing the leaf
with a wet sponge. It is more effectual to follow the bath of oxalic acid
by applying a solution of one part hydrochloric acid to six parts of
water, after which bathe in cold water, and dry slowly. Or an infusion of
hypochlorite of potash in twice its volume of water may be used instead
of the preceding.

If a leather-bound book has grease on its cover, it can be removed by
scraping French chalk or magnesia over the place, and ironing with a warm
(not hot) iron. A simpler method is to apply benzine to the grease spots,
(which dissolves the fatty material) and then dry the spot quickly with a
fine cloth. This operation may be repeated, if not effectual at the first
trial. The same method of applying benzine to oily spots upon plates or
engravings, will remove the stains.

Ink-stains may also be taken off from the leather covers of books bound
in calf or morocco by the use of oxalic acid. Care should be taken first
to try the acid on a piece of similar leather or on a discarded book of
the same color. If the leather is discolored after removing the black
spot, one may apply, after taking out the traces of oxalic acid by some
alkali, a coloring matter similar to the tint of the leather.

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 sam