The following general remarks on the removal of stains appeared anonymously in the English Mechanic. To proceed with any degree of certainty in endeavours to remove stains, they must be divided into three classes, as each variety will require a peculiar treatment. The first class comprehends those stains which do not in any way affect the nature of the material or colour, but simply alter its appearance, and which can be removed by the application of one agent alone. These may be designated Simple Stains. The second division includes such as are produced by two or more substances conjointly, and which consequently require the employment of several cleaning agents. These are known as Mixed Stains. In the third category may be placed such stains as are produced by bodies which alter or destroy the colour.

In the first class are water, oily mat' ters, vegetable juices, blood, and iron or ink stains. If water be allowed to fall on some kinds of silks, satins, or woollen fabrics, it dissolves away part of the dressing, and the consequence is that a dull spot appears on the glossy ground. To remove a stain of this nature, it is necessary to steam the spotted material until it is all equally moistened. It may then be hot-pressed, or, if small, ironed with a hot, but perfectly clean iron.

Grease spots may generally be removed from the most delicate material by the employment of benzine or oil of turpentine, care being taken that sufficient be employed to remove all line of demarcation. Ox-gall is particularly useful in extracting grease stains from woollen goods. If the stain be very thickly crusted and old, it may be sometimes advantageous to soften the grease (previous to the application of benzine) by means of a warm iron laid on a piece of thick blotting-paper which has been placed over the spot.

Tar and pitch produce stains easily removed by successive applications of spirits of turpentine, coal-tar naphtha, and benzine. If they are very old and hard, it is as well to soften them by lightly rubbing with a pledget of wool dipped in good olive-oil. The softened mass will then easily yield to the action of the other solvents.

Resins, varnishes, and sealing-wax may be removed by warming and applying strong methylated spirits. Care must always be taken that, in rubbing the material to remove the stains, the friction should always be applied the way of the stuff, and not indifferently backwards and forwards.

Most fruits yield juices which, owing to the acid they contain, permanently injure the tone of the dye; but the greater part may be removed without leaving a stain, if the spot be rinsed in cold water in which a few drops of liquor ammonia have been placed before the spot has dried. Wine also leaves an ugly stain on white materials; from these it may be removed by rinsing with cold water, applying locally a weak solution of chloride of lime, and agaia rinsing in an abundance of water. The dressing must again be imparted by steaming, starching, and hot-pressing.

Fresh ink and the soluble salts of iron - such as are used by photographers in their developing solutions, etc. - produce stains, which, if allowed to dry, and especially if afterwards the material has been washed, are difficult to extract without injury to the ground. When fresh, such stains yield rapidly to a treatment with moistened cream of tartar, aided by a little friction, if the material or colour is delicate. If the ground be white, oxalic acid, employed in the form of a concentrated aqueous solution, will effectually remove fresh iron stains. Acids produce red stains, on blacks, blues, and violets, made from the vegetable colours (except indigo). If the acid has not been strong enough to destroy the material, and the stains are fresh, the colour may generally be restored by repeated soakings in dilute liquor ammonia, applied as locally as possible. Photographers frequently stain their clothes and cloths with nitrate of silver. The immediate and repeated application of a very weak solution of cyanide of potassium (accompanied by thorough rinsings in clean water) will generally remove these without injury to the colours.

Mixed stains are generally produced by spilling sauces, gravy, or, by inadvertently rubbing against wet paint, cart-grease, gome, etc. Sauce usually contains oily or greasy matter, blood and vinegar, or some fruit-juice; hence the first step consists in removing the grease by means of ox-gall or benzine, then the acid of the vinegar or juice is neutralized by means of weak ammonia, when a final rinse in cold water will extract the blood, etc.

Most fruit-juices, wines, jam, etc.,leave stains that will require a preliminary washing with water, to remove sugary matter, treatment with very dilute ammonia to neutralize the acid, and exposure while damp to the fumes of burning sulphur. But the action of this agent must be localized as much as possible to the spot where the stain occurs, and it must be used with the greatest circumspection, for it bleaches nearly all vegetable colours, though many of them regain their force on exposure to air.

Paint stains may be treated with oil of turpentine to remove the oil, with oxygenated water to oxidize the lead, and finally, with dilute acetic acid. If the paint contains oxide of iron, oxalic acid will have to be used, while the copper colours must be treated with liquor ammonia.

Old ink stains require treating first with protochloride of tin, to deoxidize the iron, and then with dilute oxalic acid. If the material be white, it may be touched with a dilute solution of chloride of lime on the part stained, and then thoroughly washed.

Lubricants generally contain, besides grease, oxide of iron worn off the machinery, etc, hence the grease must first be extracted by means of benzine, ox-gall, ammonia, etc, and then the spot treated with oxalic acid or chloride of lime water, or even lemon-juice, if the material is very delicate. Rinsing must always follow the application of these agents.