Your beautiful copper jewelry, which started out so shiny and sparkling, has gradually lost its rosy luster. Over time, the jewelry has become chocolate brown - maybe even black. What is going on? Tarnish.
Copper, like most metals, is susceptible to an electrochemical reaction with the atmosphere. The metal’s surface interacts with molecules in the surrounding air to form a layer of corrosion (think rust). This corrosion starts out barely noticeable, but will continually become thicker and more noticeable. There are many factors, including humidity, the oils on our skin, and exposure to other chemicals that will determine the rate and color of tarnish on your copper jewelry.
Like most things, beauty is in the eye of the beholder. We call this layer a “patina” when it looks nice and artistic, and a “corrosion layer” when it has gone too far. Left unchecked, the corrosion can eventually cause pitting as the copper is slowly dissolved.
Tarnish is inevitable, but can be slowed by storing your jewelry away from humidity. Assuming you don’t have a spare vacuum chamber available, store your copper jewelry in a sealed plastic bag to limit its exposure to air. At the very least, avoid storing your jewelry in the bathroom!
If you are determined to prevent your copper jewelry from changing color, you can consider coating it with a clear lacquer or nail polish. This will create a physical barrier to keep the copper from interacting with the atmosphere. I personally choose not to coat my copper jewelry this way since I prefer the tarnish over the fumes when applying this treatment.
There are quite a few ways to remove the tarnish layer and restore your copper jewelry’s original shine. As a jeweler, I have easy access to a hot pot of citric acid pickle and a tumbler. Since you probably don’t, let me suggest a couple easy ways to remove copper tarnish.
Micro-abrasive polishing pads. These little foam pads can do miraculous work on tarnish. Each pad is covered with micro-abrasives that gently buff and polish the tarnish away without scratching the metal. These pads are very simple, make no mess, and can be reused over and over again.
Ketchup. Yes, ketchup (or is it catsup?) is a very effective, readily available remover of tarnish on copper. Learn how to clean copper jewelry with ketchup.
Do you have a favorite method of preventing or removing copper tarnish? Please share in the comments below.