Numistify guide
How to Store and Protect a Coin Collection
Bad storage ruins more coins than anything else, and most of the damage is avoidable. Here is what to keep coins in, what to keep them away from, and how to look after a collection for the long term.
The short answer
Keep coins in inert holders — Mylar or polypropylene flips, cardboard 2x2s with Mylar windows, hard capsules, PVC-free albums or grading-service slabs — in a dry place away from heat. Avoid soft PVC flips, whose residue can damage coins permanently, and keep valuable coins in a safe or a bank safe-deposit box.
The PVC problem
Many soft, flexible plastic coin flips contain PVC, a chemical added to make the plastic pliable. Over time it leaches out and collects on the coin. NGC notes that even new coins can be affected, and that the thick green, oily residue is the most destructive form, able to cause irreversible damage.
If a holder feels soft and oily, or a coin shows a green or hazy film, move the coin to a safe holder straight away. For a valuable coin that already has residue, use a professional conservation service such as NCS rather than cleaning it yourself; see should I clean my coins?
Safe holders
Hard flips. Unplasticized flips made of Mylar (polyester) or polypropylene. NGC and NCS recommend hard flips, and note that flips are meant for short-term storage.
2x2 cardboard holders. Cardboard with a Mylar window, stapled shut. Cheap and easy to label; flatten the staples so they cannot scratch neighbouring coins.
Capsules. Hard plastic capsules give a coin its own sealed space, which suits better coins and proofs.
Albums and folders. Choose ones sold as PVC-free; they are good for organising a set.
Grading holders. The sealed holders of PCGS and NGC are made for long-term storage. Never open one.
What to keep away from coins
Soft PVC flips; rubber bands, which contain sulfur that blackens silver; tape and paper clips; ordinary envelopes and acidic paper; and loose storage in jars or bags, where coins rub against each other and pick up marks.
Moisture and heat
Humidity and heat speed up toning, spotting and corrosion. Keep coins in a cool, dry place — not an attic or a damp basement — and add silica gel packets to storage boxes or a safe, replacing them when they are saturated. Check your coins from time to time instead of locking them away for years.
Handling
Hold coins by the edge, over a soft surface, with clean dry hands or gloves. Skin oils leave marks on coin surfaces, and proofs show every fingerprint.
Security and records
For a valuable collection, use a sturdy safe or a bank safe-deposit box, and ask your bank and your insurer exactly what is covered — standard home insurance may not cover a coin collection in full. Keep an inventory with photographs, separate from the coins, so the collection can be identified and valued if anything happens.
Questions people ask
What is PVC damage on coins?
A residue left by soft plastic flips that contain PVC, a chemical that makes plastic pliable. It leaches out over time and collects on the coin, sometimes as a green, oily film, and it can damage the surface permanently.
What are the safest coin holders?
Hard, unplasticized flips made of Mylar (polyester) or polypropylene, cardboard 2x2 holders with a Mylar window, hard plastic capsules, albums sold as PVC-free, and the sealed holders of grading services.
How should I store valuable coins long term?
In inert holders, in a dry place away from heat, inside a safe or a bank safe-deposit box. Keep an inventory and photographs, and ask your bank and insurer what is covered.
Should I remove PVC residue myself?
Move the coin out of the PVC holder straight away. For a valuable coin with residue, use a professional conservation service such as NCS rather than trying to clean it yourself.
Are coin albums safe?
Albums and folders sold as PVC-free and acid-free are fine for display and organisation. Avoid old albums with soft plastic slides or acidic paper, and keep any album away from moisture.
Related guides
Should I clean my coins? — and when professional conservation makes sense.
How to track a coin collection — keeping the inventory.
Need to track your collection?
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