How Long Does It Take for Brass to Rust?

Brass, beautiful and durable, seems a ubiquitous material in modern life. From hidden plumbing elements to shiny brass candlesticks, it enhances our lives with its beauty and utility. One of brass's ever-present properties is its tendency to tarnish when not protected from the environment. Similar to rust, tarnish is a feature that is both loved and hated by brass lovers. If you were wondering how long it takes brass tarnish, there are many considerations.

A well-cared-for brass door knocker, free of tarnish.


Brass is a metal consisting of copper alloyed with nickel. The result is a hard metal that is durable, corrosion-resistant and antimicrobial. Brass is machinable and can be shaped in molds. It also conducts heat and carries electricity easily. Its copper or gold color mimics more expensive metals. The physical and aesthetic qualities of brass have made it an essential part of human life since ancient times.


Tarnish is a mild form of corrosion caused by exposure of copper to the environment. Salt, in particular, tarnishes brass quickly and must be kept away from brass intended to be kept shiny. Chemicals in rainwater, tap water and air, as well as those found on our fingers and in food, are also corrosive.

Tarnish Timing

How fast brass tarnishes depends on how it is handled and what elements it is exposed to. If you handle a brass candlestick and put it away without wiping it free of the oil and salt from your fingers, it will turn brown rather quickly. Likewise, exterior lanterns left exposed to the elements will tarnish faster than interior fixtures. Coppery fingerprints can show up on a freshly polished surface within days, while interior lighting fixtures never touched by oily fingers could take months to show even the slightest dulling.

Managing Tarnish

If you appreciate the patina of age on your belongings, allow your brass treasures to darken without interference. An aged finish should not be contaminated by salts and acids -- such as found in salad dressings -- because they will remove a desirable patina. If you prefer a shine, keep your fingers off polished surfaces and, if possible, and polish them often. If you want a permanent shine, consider having your brass lacquered by a professional. If your brass is already lacquered, don't use metal polishes or solvents for cleaning, as they remove lacquer.