The bactericidal properties of brass have been observed for centuries, particularly in marine environments where it prevents biofouling.
Depending upon the type and concentration of pathogens and the medium they are in, brass kills these microorganisms within a few minutes to hours of contact.
The so-called dezincification resistant (DZR or DR) brasses, sometimes referred to as CR (corrosion resistant) brasses, are used where there is a large corrosion risk and where normal brasses do not meet the standards.
Applications with high water temperatures, chlorides present, or deviating water qualities (soft water) play a role. This brass alloy must be produced with great care, with special attention placed on a balanced composition and proper production temperatures and parameters to avoid long-term failures.
In April 2001 manufacturers agreed to reduce lead content to 1.5%, or face a requirement to warn consumers about lead content.
Keys plated with other metals are not affected by the settlement, and may continue to use brass alloys with higher percentage of lead content.
Tin has a similar effect and finds its use especially in seawater applications (naval brasses).For the same reason, some low clarinets, bassoons and contrabassoons feature a hybrid construction, with long, straight sections of wood, and curved joints, neck, and/or bell of metal.The use of metal also avoids the risks of exposing wooden instruments to changes in temperature or humidity, which can cause sudden cracking.The density of brass is 8.4 to 8.73 grams per cubic centimetre (0.303 to 0.315 lb/cu in).Because brass is not ferromagnetic, it can be separated from ferrous scrap by passing the scrap near a powerful magnet.