Most challenge coins are made to be carried - handled daily, tucked into pockets, pressed into palms during a coin check. That everyday use is part of their meaning. But if you are building a collection you intend to preserve, display, or eventually pass on, the way you store and present your coins matters enormously.
The enemies of a coin collection are simple: humidity, light, contact damage, and the wrong kind of plastic. None of them are difficult to manage once you understand what you are dealing with.
Understanding What Damages Challenge Coins
Challenge coins are typically struck in brass, bronze, zinc alloy, or steel, then plated in gold, silver, nickel, or antique finishes. Some include soft enamel or hard enamel colour fills. Each component reacts differently to environmental conditions.
Humidity and Moisture
Moisture is the primary culprit for tarnish, corrosion, and enamel lifting. Coins stored in damp environments - basements, bathrooms, poorly ventilated display cases - will develop oxidation over time. The plating process protects the base metal to a degree, but any chip or scratch in the plating becomes an entry point for moisture-driven corrosion.
PVC Off-Gassing
This one surprises collectors who are new to the hobby. Many cheap coin holders, soft plastic flips, and display pages contain PVC (polyvinyl chloride). PVC releases plasticisers over time - a greasy, acidic film that adheres to coin surfaces, softens enamel, and can cause irreversible damage. The effect is slow and often mistaken for normal tarnish until it is too late.
Avoid These
Soft vinyl coin flips, cheap plastic display sheets, and any holder labelled simply "plastic" rather than "PVC-free" or "archival." If you can bend the holder easily and it has a slightly oily feel, it likely contains PVC. Replace it.
Light and UV Exposure
Prolonged exposure to direct sunlight fades enamel colours and can bleach or discolour certain finishes - particularly antique bronze and gold plating. UV filtering is especially important for display cases positioned near windows.
Contact and Abrasion
Coins stored loose together will scratch each other's surfaces and edges. Even gentle contact over time produces micro-scratches that dull the finish. Each coin should be stored separately or with a protective barrier between pieces.
Storage Options
The right storage solution depends on how many coins you have, how frequently you access them, and whether display is a priority.
Air-Tite Capsules
Hard acrylic capsules that snap shut around the coin, creating an airtight seal. The gold standard for individual coin protection. Available in multiple sizes to fit standard challenge coin diameters (typically 38mm to 50mm).
PVC-Free Coin Flips
Two-pocket rigid plastic holders that fold over the coin. Convenient for access and labelling (the second pocket holds a card). Must be specifically labelled Mylar, polyethylene, or PVC-free.
Velvet-Lined Trays
Coin trays with individual circular recesses keep coins separated and cushioned. Good for collections you want to view all at once without removing each coin from a holder.
Archival Coin Albums
Binder-style albums with PVC-free pages containing individual coin pockets. Convenient for large collections - easy to organise, label, and browse. Confirm pages are archival-grade before purchasing.
Presentation Boxes
Original presentation boxes from the issuing organisation are worth keeping with the coin - they document provenance and add collector value. Store in a cool, dry environment. Do not keep them in the basement.
Anti-Tarnish Pouches
Fabric pouches treated with anti-tarnish compounds that absorb airborne sulphur - the main cause of silver and copper tarnishing. Useful for collections with a lot of silver-plated or antique-finished coins.
Display Options
A collection that is never seen is only half a collection. Displaying challenge coins properly means choosing a format that shows them off while protecting them from the environmental factors above.
Shadow Boxes
The classic choice, and for good reason. A shadow box is a framed display case with depth - typically 2 to 4 inches - that allows coins to be mounted at a slight angle or laid flat against a backing. Military-style shadow boxes often pair coins with unit patches, photos, ribbons, and other memorabilia, creating a curated display of a period of service.
When choosing a shadow box, look for UV-protective glass (not standard glass) and a backing material that will not off-gas. Acid-free foam or velvet-covered board are the standard choices. Coins are typically mounted using foam coin mounts, acrylic risers, or simply recessed into cut foam.
Shadow Box Tips
- Hang away from direct sunlight - even UV glass reduces but does not eliminate UV transmission
- Avoid exterior walls in cold climates, where temperature differentials cause condensation inside the frame
- Use museum-quality acid-free backing board, not standard cardboard
- Label each coin on the backing - future owners will thank you
Wall-Mounted Coin Displays
Dedicated challenge coin display racks and boards are widely available. These range from simple wooden boards with coin-sized holes or slots to purpose-built acrylic wall panels with individual coin pockets. The advantage over a shadow box is modularity - you can add rows as your collection grows rather than replacing the entire frame.
For wall displays, look for options with a backing that prevents coins from touching each other when mounted side-by-side. Felt or foam-lined pockets are preferable to bare slots where coin edges can contact each other.
Desktop Display Stands
Individual display stands - either single-coin easels or multi-slot horizontal racks - keep a rotating selection of your most significant coins visible on a desk or shelf. These work well as a "current highlights" display while the bulk of the collection is stored properly elsewhere.
Acrylic easel stands are the most common and inexpensive option. For valuable coins, choose stands that grip the edge rather than the face of the coin.
Glass-Topped Display Cases
For larger collections or installations in dedicated spaces, horizontal display cases with glass or acrylic lids allow full viewing without removing individual coins from their holders. Museum-style cases with UV-filtering glass offer the best long-term protection for display. These are the right choice for anyone displaying coins with significant monetary or historical value in a public or semi-public setting.
Environmental Controls
Regardless of the holders and cases you choose, the environment matters. Ideal conditions for coin storage:
- Temperature: 60-70°F (15-21°C) - stable is more important than cool; avoid places with large temperature swings
- Relative humidity: 40-50% - below 60% consistently. A cheap digital hygrometer in your storage area is worth the investment
- Light: Away from direct sunlight and minimise fluorescent light exposure for displayed coins
- Air circulation: Avoid sealed airtight rooms where humidity can build - moderate airflow is better
"A $10 hygrometer and a small silica gel canister in your display case can protect a collection worth thousands. The equipment costs almost nothing - the damage it prevents can be irreversible."
Silica gel packets are a low-cost way to manage humidity within a closed case or storage box. The colour-changing variety indicates when they are saturated and need replacing or recharging.
Cleaning Challenge Coins
The general rule in numismatics applies here: when in doubt, do not clean. Overcleaning is one of the most common ways collectors reduce both the appearance and value of their coins.
What to do - and not do:
- Do: Wipe with a soft, dry microfibre cloth to remove dust and fingerprints. Handle coins by the edges, not the face, to avoid transferring skin oils
- Do: Use a slightly damp cloth (distilled water only) for surface dirt. Pat dry immediately and allow to air dry before returning to storage
- Do not: Use silver polish, brass cleaner, or any abrasive compound on plated coins. These remove the plating along with the tarnish
- Do not: Use ultrasonic cleaners on coins with enamel fills. The vibration can crack or detach enamel
- Do not: Rub vigorously. Even soft cloths produce micro-scratches under pressure
For valuable coins with significant tarnish or corrosion, consult a professional numismatic conservator rather than attempting DIY cleaning. The cost of professional conservation is almost always less than the value lost through incorrect cleaning.
Photographing and Documenting Your Collection
Storage and display solve the physical preservation problem. Documentation solves the provenance and insurance problem.
Photograph each coin - both sides, in good natural light - and record what you know about its origin: where you got it, who gave it, what unit or organisation issued it, and any known history. Store these records separately from the coins themselves, ideally in cloud storage as well as a local copy.
For collections with significant monetary value, a rider on your home insurance policy is worth investigating. Standard home contents policies often exclude collectibles above a modest per-item limit, and a separate scheduled items policy is straightforward to obtain once you have documentation of what you own.
Travelling with Challenge Coins
If you carry coins - for a coin check, for a presentation, or simply as part of your everyday kit - a purpose-made challenge coin holder or belt pouch protects the coin from the worst pocket hazards: keys, change, and hard edges.
For transporting a collection to a show or event, individual air-tite capsules inside a padded case or foam-lined box are the safest option. Never transport loose coins in a bag where they can contact each other or harder objects.
Ready to Share Your Collection?
Once your coins are properly stored and displayed, the next step is connecting with other collectors. Our community gallery lets you show off what you have, discover coins from collectors worldwide, and explore trade opportunities for pieces you are looking to add or move on.