Cleaning brass properly can restore the luster to the metal, bringing back the warm golden color which makes brass so popular for things like door knobs and candlesticks. Improper cleaning can actually increase the tarnish, blackening or discoloring the brass, or it can simply end in a lackluster cleaning result, in which much of the film and tarnish is intact. Fortunately, cleaning brass is not very difficult.
Before you start cleaning brass, you should confirm that you are really working with brass. True brass is not magnetic, so if you bring a magnet up to a “brass” fixture and the magnet sticks, the metal is not brass, and it will need to be cleaned differently. Once you have determined that you are working with real brass, you should see if you need to remove a film of dust and dirt, or a tarnish in the metal itself.
Brass is typically lacquered to reduce tarnish, because it tarnishes very easily when exposed to the air. If you just have a film of dirt, wash the brass in mild soapy water, with a few drops of vinegar added for stubborn stains. You can also use rubbing alcohol to polish brass.
If the brass is discolored because of tarnish, you will need to strip the lacquer. Some commercial brass cleaners remove the lacquer, or you can use a varnish remover. Polish the tarnish away with vinegar, salt, or a commercial brass tarnish remover, wash the brass with warm soapy water, and allow it to dry completely before applying a fresh coat of lacquer to prevent tarnish.
Regularly cleaning brass fixtures with a soft cloth is an excellent idea, as it reduces the chances of allowing a film to build up. Regular polishing also allows people to keep an eye out for early signs of tarnish, so that rapid action can be taken to clean up the tarnish and relacquer the brass before it becomes damaged. Commercial brass polishing products can also be periodically applied to polish and buff brass, although these should be used sparingly to prevent the brass from blackening.
There are some special tools which can be used for cleaning brass, such as brass buffers which will penetrate into cracks and crevices of brass fixtures to remove tarnish and cleaning materials. In the case of an especially soiled, tarnished, or complex brass fixture, it may be a good idea to take the brass to a professional for cleaning and relacquering, and to polish it more regularly in the future to prevent a buildup of dirt.