Copper reacts to an array of chemicals, why copper cookware is always lined in another metal. This is great when I’m applying patinas, because I can get beautiful colors, but less fun when it’s involuntary. I often refer to copper—and its alloys brass and bronze—as a “living finish” because you’ll be happiest if you expect it to grow with you over time, rather than trying to fight its nature. After all, one person’s tarnish is another’s artistic patina!
First, medical disclaimer. If you search on this topic, you’ll find articles which claim green skin from copper can be “corrected” via diet, and some which link it to serious medical issues. Naturally if you’re having health problems, suddenly develop this reaction, or have a rash, consult a physician. But there are also many people who simply get a bit of green rub-off, which I tend to view as no different from freckling vs. tanning, or the genes which make me a mosquito magnet.
Pretty much anything can cause copper to change color and occasionally even develop a crust:
- Body oils
- Water (especially sweat, pools, and seawater)
- High heat
Wiping or rinsing off sweat, making sure your pieces are dry, and storing in a jewelry box or zip bag all help slow tarnish.
High wear zones
Friction doesn’t cause reactions, instead it acts like continuous polishing, rubbing away protective coatings and even deliberate patinas. (I’m doing a test on four finishes right now, and will be posting results in another few weeks.) This tends to be the order from light to heavy wear:
- Cuff bracelets (on the topside)
Some of my pieces are sold bright with no coatings. Others are “antiqued” and may be uncoated or have Renaissance Wax applied (see below).
I generally recommend using a cloth, such as a Sunshine Polishing Cloth. It’s gentle, lets you buff in highlights and is safe with stones and beads.
You can also polish copper, brass, and bronze by dipping. I use straight white vinegar, but stand there or set a timer for a couple minutes because it acts quickly. (Letting pieces linger in the acid can cause fine pitting on the surface, which gives tarnish a greater foothold in the future.) After the vinegar, immerse in a solution of baking soda and water until it stops bubbling, and then wash and dry well. Almost any acid, or acid+salt combination is effective—lemon juice and even ketchup are popular.
The goal is a transparent, permanent barrier between metal and environment—which is naturally impossible. Everything wears off, at unpredictable rates because we’re all different, but there are ways to slow it down. (Note any sealant can shift the color as it’s being applied, and if a piece has been ink tinted the dyes can bleed.)
|Pros||Easy to apply, wears gracefully without flaking, and additional coats can be applied as needed.|
|Cons||Less enduring and impermeable than lacquers (not recommended as allergy protection).|
|Use||I use Renaissance Wax, which was developed to protect fine art. Apply a thin layer, let dry a few hours, and then buff with a soft cloth such as a scrap of old tee.
I’ve heard reports of furniture, auto, and floor waxes being effective, but do not have personal experience with them.
|Pros||Long lasting and tough protection.|
|Cons||May chip as it wears off, and can be difficult to remove without abrasives, harsh solvents and/or flame.|
|Use||I use Permalac. Equally recommended (though I haven’t used it myself) is Everbrite ProtectaClear. There are fans of both brush and spray application, but with both you’ll want to apply multiple thin coats, let dry between coats, and then let it completely cure.
Again, people have used everything from auto body coatings to fingernail polish. The two I recommend are industrial coatings designed for metal and environmental protection, but they can be difficult to find in small volumes.