To remove from parchment or paper stains made with ordinary writing ink, apply spirit of salts (hydrochloric acid) diluted with five or six times its bulk of water. Solutions of either oxalic, citric, or tartaric acids are said to produce the same results; but in any case the acid must be washed off with clean water a minute or two after application. Experiment on odd pieces of parchment or paper before touching any valuable work, as some little skill is required. To remove ink stains from imitation ivory, wipe over several times with 1 oz. of oxalic acid dissolved in 1/2 pt. of hot water. Should this be of no avail, rub the surface with fine glasspaper till all marks are removed; then repolish with putty powder and oil, applied with felt or cloth: finish with dry powder and chamois leather. A solution of 1 oz. of citric acid in 4 oz. of water will remove all traces of writing ink from paper. This does not touch printers' ink, which indeed cannot be removed by the mere application of a bleaching agent. To remove ink or ironmould stains from linen, moisten the latter by holding it in steam, then apply weak hydrochloric acid on a piece of stick. Wlien the stain is dissolved out, wash the article well to remove all acid.
To remove old ink stains from wood, rub the stains with muriatic acid, allowing the acid to remain for a few minutes; then sponge off with clean water. Spirit of salts may be used to remove old ink stains from wood: great care is required, especially if the stains are on a veneer. Another method is to apply spirit of nitre with a feather, and when the ink has disappeared to wash off with cold water. Another; use salt of lemons (binoxalate of potassa) moistened with water. Another; put some powdered crystals of oxalic acid on the ink stains, moisten with hot water, and rub them in. The oxalic acid will dissolve most of the otherwise insoluble ingredients of the ink, and the stain can be washed out with water. If this is not effective, try a solution of freshly made chloride of lime.