This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Pour benzol (not benzine or gasoline, but Merck's "c. p." crystallizable) on calcined magnesia until it becomes a crumbling mass, and apply this to the spot, rubbing it in lightly, with the tip of the finger. When the benzol evaporates, brush off. Any dirt that remains can be removed by using a piece of soft rubber.
If the foregoing fails (which it sometimes, though rarely, does), try the following: Make a hot solution of sodium hydrate in distilled water, of strength of from 3 per cent to 5 per cent, according to the age, etc., of the stain. Have prepared some bits of heavy blotting paper somewhat larger than the spot to be removed; also, a blotting pad, or several pieces of heavy blotting paper. Lay the soiled page face downward on the blotting pad, then, saturating one of the bits of blotter with the hot sodium hydrate solution, put it on the stain and go over it with a hot smoothing iron. If one application does not remove all the grease or stain, repeat the operation. Then saturate another bit of blotting paper with a 4 per cent or 5 per cent solution of hydrochloric acid in distilled water, apply it to the place, and pass the iron over it to neutralize the strong alkali. This process will instantly restore any faded writing or printing, and make the paper bright and fresh again.
For certain kinds of obstinate spots (such as coffee and chocolate, for instance) there is no better detergent than glycerine, especially for fabrics with delicate colors. Apply the glycerine to the spot, with a sponge or otherwise, let stand a minute or so, then wash off with water or alcohol. Hot glycerine is even more efficient than cold.