Acids should never be employed in cleaning brass, as the metal soon becomes dull after such treatment. The application of olive oil and very fine tripoli, followed by a washing with soap and water, constitutes the best method of polishing and preserving the brilliancy.
(2) Use sweet oil and whiting.
(3) To clean brass, rub the surface of the metal with rotten-stone and sweet oil, then rub off with a piece of cotton flannel, and polish with soft leather. A solution of oxalic acid rubbed over tarnished brass soon removes the tarnish, rendering the metal bright. The acid must be washed off with water, and the brass rubbed with whiting and soft leather. A mixture of muriatic acid and alum dissolved in water imparts a golden color to brass articles that are steeped in it a few seconds.
(4) The government method prescribed for cleaning brass, and its use in all the United States arsenals, is claimed to be the best in the world. The plan is to make a mixture of one part common nitric and one-half part sulphuric acid in a stone jar, having also ready a pail of fresh water and a box of sawdust. The articles to be treated are dipped into the acid, then removed into the water, and finally rubbed with the sawdust. This immediately changes them to a brilliant color. If the brass has become greasy, it is first dipped in a strong solution of potash and soda in warm water; this cuts the grease, so that the acid has free power to act.
(5) In cases where brass cannot be successfully cleaned with oxalic acid it should be rubbed with potash lye and then plunged in a mixture of equal parts of sulphuric acid, nitric acid and water, and then washed, rinsed, dried and polished.
(8) To remove the stains of iodide potassa and aqua ammonia stains off brass, scour with a mixture of ammonia water, alcohol, and chalk. For delicate work the chalk should be finely levigated. For heavy work powdered bath brick, rotten stone, red brick dust, or Tripoli in sweet oil may be rubbed on with a flannel, and the article polished with leather. The government method has been to dip the article in a mixture of two parts nitric acid and one part sulphuric acid, immediately removing to water, and finally rubbing with sawdust. Grease is removed with alkali.