Stop brass from tarnishing by applying multiple thin coats of clear lacquer to the brass on a periodic basis. The application of lacquer prevents exposure of the brass to air. Exposure to air oxidizes the copper and zinc in the brass, creating a green patina that some consider undesirable.
Remove tarnish from brass before applying lacquer. Many metal polishes contain solvents designed to remove the tarnish. Acidic products such as household ammonia or lemon juice can serve the same purpose. Mix these products with salt to create a paste to scrub the tarnish off the brass. Apply the paste with a soft cloth or with a rotary-head tool with a polishing head. Once the tarnish is removed, rinse the paste off with clean water.
Brass is often used in the construction of door knobs, ammunition, musical instruments and electrical and plumbing hardware because of its low friction property. It has a bright, yellow color similar to gold and is often used for decorative purposes. It is a soft metal that does not produce sparks when struck, making it an ideal metal for situations where a spark could create an explosion. Lead is often added to brass used in the construction of machinery.