To polish brass, use ordinary whiting or chalk and a damp cotton or woolen cloth. If the metal is stained or tarnished, then use rotten stone and oil on a cloth, and finish with whiting for a gloss. If corroded and blackened, use oxalic acid in water with the rotten stone, instead of oil.
To polish cartridges, wet 10 parts of emery dust and 50 parts of elutriated quartz with 100 parts of a 30 per cent. gum tragacanth solution, the mass being given the requisite consistency with a solution of 100 parts of soap dissolved in 150 parts spirits of wine.
(2) Infusorial earth, either alone or impregnated with oleic, is a good polish for cartridges.
Copper parts are polished by rubbing them with rotten stone and oil, followed by an application of a flannel rag, and finally with leather. If a solution of oxalic acid is applied to dull brass, the layer of oxide is quickly removed and the metal uncovered. The next step is to wash off the acid with water and rub the brass with soft leather.
Articles plunged in a solution of hydro-chloric acid with alum, triturated with water for a few seconds, are given a golden color. A pretty color, ranging between orange and gold, is given polished copper by its brief immersion in a solution of crystallized acetate of copper. A violet color is given copper by its brief plunging in a solution of chloride of antimony, followed by its rubbing with a stick enwrapped with cotton.
Polish gold with jewelers' rouge, mixed with alcohol, and applied to the buff-stick.
To polish nickel watch movements which have become stained, add 1 part of sulphuric acid to 50 parts of rectified alcohol, and place the parts to be polished in this fluid for about 15 seconds, immersing also only a few at a time so as to be enabled to take them out at the proper time, a longer immersion being harmful. After taking them from this bath, rinse the parts in clean water and put them for a few minutes in rectified alcohol; then dry them in sawdust or with soft linen. Nickel watch movements which have been cleaned by this method have practically the appearance of being new, as their smooth surface is not marred at all, as would be the case if a file were used.
A scouring paste, said to be of the very best, consists of oxalic acid, 1 part; iron peroxide, 15 parts; powdered rotten stone, 20 parts; palm oil, 60 parts; petrolatum, 4 parts. Pulverize the oxalic acid and add rouge and rotten stone, mixing thoroughly, and sift to remove all grit; then add gradually the palm oil and petrolatum, incorporating thoroughly. Add oil of myrbane or oil of lavender to suit.
A good polishing paste for brass is made by the dissolution, in 120 parts of boiling water, of 15 parts oxalic acid, and to this is added 500 parts of pumice powder, 60 parts salt soap, 60 parts of any kind of fat and 7 parts of oil of turpentine.