To remove rust from polished steel articles the spots affected should be soaked for several days with oil, and then scoured with tripoli and oil, or with emery, a piece of hard wood being used for this purpose. The oil and all other impurities are then to be wiped off. The stains are to to be rubbed a second time with emery and wine vinegar and then polished with fine bloodstone and leather.
To thoroughly clean iron from rust, first immerse it in deeply saturated solution of chloride of tin. The length of said bath should be dependent on the thickness of the film of rust. As a general rule, however, from twelve to twenty-four hours will be amply sufficient. Care should be taken that this solution of the chloride of tin should not contain too heavy an assiduous excess, otherwise the iron itself will be attacked. After the removal of the articles from the bath they should first be washed in water followed by a second washing with ammonia, and then dried as rapidly as possible. Articles thus treated primarily assume the appearance of dead silver, but regain their natural appearance by simply polishing.
A good compound to prevent metals from rusting is made by melting 1 ounce of resin in a gill of linseed oil and mixing it with 2 quarts of kerosene oil while warm.
To prevent steel from rusting, brush it with a solution of paraffine and benzine.
To free nickel-plated articles from rust, grease the rust stain, and a few days thereafter rub them thoroughly with a cloth wet with ammonia. The dissolution of the rust is effected by the ammonia without harm to the plating. If this method does not work satisfactorily, the stains may be touched with diluted hydro-chloric acid and vigorously rubbed. They should then be washed, and on becoming dry polish with tripoli or some similar polishing material.
To extract rust from steel, plunge the article to be cleaned in a strong solution of cyanide of potassium consisting of 1/2 ounce in a wineglass of water, for a few minutes, and then take it out and clean with a small brush, such as a toothbrush, dipped into a composition of castile soap, cyanide of potassium, whiting and water made into a paste of about the thickness of ordinary cream.
Schweinfurt green is made by boiling a mixture of:
10 6-10 parts Acetic Acid, 31 26-100 parts Cupric Oxide, 58 65-100 parts Arsenious Acid.
It is very poisonous.
To brighten articles in relief, scratch-brushes are used oftener than store or steel burnishers. A common scratch-brush is constructed of a large number of hardened brass wires selected from a coil of large diameter, so that there will be little tendency of the wires, when in place, toward curvature. For the manufacture of a good scratch-brush select a coil of brass wire of the right fineness and bind tightly with strong twine of about 2-3 the desired length of the brush, say 6 or 7 inches. Cut the bundle of wire close to the cord at one end, and about 2 inches from the other, with a chisel. The close cut end is to be dipped into a neutral solution of chloride of zinc and plunged into molten tin, which solders all the wires and guards against their separation. This, too, is preferably fixed by means of another string to a thin wooden handle projecting above the soldered end.