How to Store Coins With Verdigris
Verdigris isn’t just a problem for the coin it appears on — it’s contagious. If you’ve got a coin with active green corrosion sitting in a flip, tube, or roll, it could be slowly eating away at everything it touches.
In our last post, we broke down what verdigris is and how to spot it. This post is all about what to do after you’ve found it.
Why Verdigris Spreads
Verdigris forms when copper reacts with moisture, oxygen, or acidic compounds like chlorides or carbonates. These reactions produce the green, powdery substance that collectors recognize as corrosion.
The scary part? Verdigris doesn’t stay put.
It can release reactive vapors or dust-like particles into confined spaces like flips, tubes, or albums. If those particles come into contact with another copper or bronze coin, especially one that’s already vulnerable due to scratches or high humidity, the corrosion can start all over again. That’s why coins with active verdigris are sometimes described as “infectious.” You’re not just storing damage, you’re spreading it.
It’s a slow process, but over months or years, it can turn a healthy coin into a crusty mess. The more reactive the environment (think: heat, humidity, PVC residue), the faster the problem grows.
Best Practices for Storing Verdigris-Affected Coins
If a coin in your collection already shows signs of verdigris. Treat it like a biohazard, because in a way, it is. Even a small amount of active corrosion can spread to nearby coins if they’re stored together in flips, tubes, or albums.
Store any coin with visible verdigris separately. Airtight holders are best, but even a simple 2×2 cardboard flip in a separate box can keep it from infecting the rest of your collection. Monitor the coin over time. If it continues to worsen, it may need professional conservation. Never store a verdigris coin in contact with paper, PVC, or in high humidity.
Taking preventative steps now could save multiple coins from damage down the line. This is one of the rare times in collecting where quarantining actually makes sense.
Final Thoughts
Verdigris might seem like a minor annoyance, just a green spot here or there, but it has the potential to do real damage if left unchecked. It’s not just an issue of one coin looking a little worse; it can quietly ruin an entire tube or album over time. Isolating affected coins and storing them properly is one of the easiest ways to protect the rest of your collection.
If you spot that telltale green crust, don’t ignore it. Keep it contained, stay aware, and your collection will thank you.