This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
To clean brasses quickly and economically, rub them with vinegar and salt or with oxalic acid. Wash immediately after the rubbing, and polish with tripoli arid sweet oil. Unless the acid is washed off the article will tarnish quickly. Copper kettles and saucepans, brass andirons, fenders, and candlesticks and trays are best cleaned with vinegar and salt. Cooking vessels in constant use need only to be well washed afterwards. Things for show—even pots and pans—need the oil polishing, which gives a deep, rich, yellow luster, good for six months. Oxalic acid and salt should be employed for furniture brasses—if it touches the wood it only improves the tone. Wipe the brasses well with a wet cloth, and polish thoroughly with oil and tripoli. Sometimes powdered rotten stone does better than the tripoli. Rub, after using, either with a dry cloth or leather, until there is no trace of oil. The brass to be cleaned must be freed completely from grease, caked dirt, and grime. Wash with strong ammonia suds and rinse dry before beginning with the acid and salt.
The best treatment for wrought steel is to wash it very clean with a stiff brush and ammonia soapsuds, rinse well, dry by heat, oil plentifully with sweet oil, and dust thickly with powdered quicklime. Let the lime stay on 2 days, then brush it off with a clean, very stiff brush. Polish with a softer brush, and rub with cloths until the luster comes out. By leaving the lime on, iron and steel may be kept from rust almost indefinitely.
Before wetting any sort of bric-a-brac, and especially bronzes, remove all the dust possible. After dusting, wash well in strong white soapsuds and ammonia, rinse clean, polish with just a suspicion of oil and rotten stone, and rub off afterwards every trace of the oil. Never let acid touch a bronze surface, unless to eat and pit it for antique effects.