Mere age stains can he removed from engravings by placing the latter in a shallow tray (a tea-tray, for instance) containing water, and exposing them to the rays of the sun till bleached, when they should be allowed to dry naturally. When dry they can be ironed with a hot iron over several folds of linen to take out all creases, etc. To remove yellow grease stains, lay a sheet of muslin in a tea-tray, and on the sheet lay the,engraving. Take the whole into the open air and with a soft wash-leather pad well sponge the yellow stain with petroleum spirit or spirit of wine. Do not in any case attempt to do this indoors or near artificial light, as the spirit is highly inflammable. When the stain has been removed, lift the muslin and engraving together from the dish to a table, and cover the face with blotting-paper, placing over this a sheet of brown paper, and then a sheet of calico. This done, turn the whole over, remove the muslin back, replace with blotting paper, brown paper, and calico, and submit the whole to gentle pressure until dry. Stains caused by damp, etc., are removed by the following method.

Cover the engraving in a glazed earthenware tray with clean rain-water till the paper is saturated; then pour off the water, and substitute a solution of chloride of lime strained through muslin. The moment the stain disappears pour the solution away, and rinse the engraving in clean water. Then dry, and ensure smoothness by stretching the paper. To remove grease stains, lay the engraving between several folds of clean blotting-paper, and pass a hot iron over it. Continually change the paper and repeat the ironing. Several applications of benzine are also effective in removing grease. Damp and age stains may be removed in the following manner. Lay the engraving in a flat dish - a sheet of glass with wooden sides dressed with paraffin wax will answer very well - and pour over it a mixture of equal parts of benzoin and concentrated solution of chloride of lime and water. Let the engraving remain till the stains disappear •, pour off the bleach, and well wash with cold water as the engraving lies in the dish. On no account attempt to take it out. After a dozen or so changes of water, let it soak for an hour in fresh water; tip up the dish, and let the engraving dry on the glass.

Very slight friction with a camel-hair brush may be applied to a particularly obstinate mark, but do not finger the paper while it is wet.