Why Proper Care is Essential for Longevity

Challenge coins are more than just pieces of metal; they are tangible symbols of honor, achievement, belonging, and history. Whether you are a service member who earned a coin for a specific mission, a corporate employee recognized for outstanding performance, or a collector who appreciates the intricate artistry, each coin tells a story. This inherent value—both sentimental and, in many cases, monetary—makes their preservation paramount. Proper care is not merely about keeping them shiny; it is about safeguarding the legacy they represent. A well-preserved challenge coin can be passed down through generations, continuing to inspire and commemorate long after the original event has passed. Conversely, neglect can lead to irreversible damage like deep scratches, permanent tarnishing, or corrosion, which diminishes both its visual appeal and its significance. For collectors, the condition is a primary factor in determining a coin's market value. A coin from a renowned challenge coin maker that is in mint condition can be worth significantly more than an identical but damaged one. Therefore, understanding and implementing a consistent care regimen is the first and most crucial step in being a responsible custodian of these prized possessions. It transforms ownership from passive holding to active preservation, ensuring that the craftsmanship invested by skilled challenge coin manufacturers endures for decades to come.

Preventing Damage and Preserving Value

The journey of preservation begins with a mindset of prevention. The most effective way to care for your challenge coins is to stop damage before it occurs. This proactive approach involves understanding the common threats: physical abrasion, chemical reactions, and environmental factors. Physical damage often comes from improper handling—coins clinking together in a pocket or drawer, being dropped on hard surfaces, or being cleaned with abrasive materials. Chemical damage arises from exposure to substances like chlorine, salt, acids from skin oils, and harsh cleaning agents. Environmental threats include excessive humidity, which promotes corrosion and mold, and extreme temperature fluctuations, which can stress the metal. By mitigating these risks, you directly preserve the coin's value. For instance, a coin commissioned when you create your own military coin is a unique artifact. Its value is tied to its pristine state as a representation of your specific unit or experience. A single deep gouge or patch of green verdigris can tell a story of carelessness rather than service. Preservation, therefore, is an act of respect for the coin's purpose and the effort that went into its creation. It ensures that the coin remains a source of pride and a valuable asset, whether within a personal collection or as part of an institutional archive.

Avoiding Scratches and Fingerprints

The moment you take a challenge coin out for admiration or showing, the risk of damage begins. The most immediate and common threats are microscratches and fingerprints. Even seemingly smooth surfaces like fabric or soft wood can contain minute abrasive particles that act like sandpaper against the coin's soft metal or delicate enamel finishes. Always handle coins by their edges, much like numismatists handle rare currency. Avoid letting the obverse (front) and reverse (back) surfaces contact any hard or textured material. Provide a clean, soft surface, such as a velvet pad or a microfiber cloth, to place the coin on if you must set it down. Fingerprints are a dual menace. The oils and salts from your skin can, over time, etch into the metal's surface, leaving permanent stains that accelerate tarnishing, particularly on silver, copper, and brass coins. Furthermore, the act of wiping off a fingerprint with your shirt or a rough cloth is almost guaranteed to cause fine scratches. The golden rule is: if you must touch the face of the coin, ensure your hands are impeccably clean and dry, and even then, minimize contact. For coins with high-relief designs, be extra cautious around the raised details, as they are most vulnerable to dings and wear.

Using Gloves When Handling Valuable Coins

For serious collectors or those handling coins of exceptional historical, sentimental, or financial value, the use of gloves is non-negotiable. This is a standard practice among professional numismatists, museums, and reputable challenge coin manufacturers when inspecting their own products. Cotton gloves, once popular, are now often discouraged as they can snag on sharp coin edges and may contain natural fibers that leave lint. The preferred choice today is lint-free, powder-free nitrile or white cotton gloves specifically designed for handling delicate items. These gloves create a perfect barrier between your skin and the coin, eliminating the risk of transferring oils, moisture, or acids. They also provide a slightly better grip than bare fingers, reducing the chance of a costly drop. When you create your own military coin with intricate, custom colors and plating, you invest in a unique piece of art. Handling it with gloves from the moment it arrives from the challenge coin maker ensures it remains in the same flawless condition for years. Make glove usage a ritual—a signal that you are engaging with an object worthy of special care and attention. Store a pair of clean gloves with your coin cleaning and viewing supplies so they are always at hand.

Gentle Cleaning with a Soft Cloth

Regular, gentle dusting is the cornerstone of challenge coin maintenance and should be your first line of defense against buildup. Over time, even in a display case, coins will accumulate a layer of dust that can attract moisture and obscure details. For this routine cleaning, use a soft, clean, lint-free cloth. Microfiber cloths designed for cleaning eyeglasses or camera lenses are ideal due to their ultra-fine fibers that trap dust without scratching. Gently wipe the coin's surface in a straight line or with the grain of any brushed metal finish—never in a circular motion, as this can create subtle swirl marks. Do not apply pressure; let the cloth do the work. If the coin is in a protective capsule, you can clean the capsule itself in the same manner. This simple practice, performed monthly or bi-monthly, removes abrasive particles before they have a chance to become embedded or cause micro-scratches. It is a preventative measure that maintains the coin's luster with minimal risk. Remember, the goal of cleaning is not to make an old coin look unnaturally new (which can destroy its patina and character), but to preserve its current state and prevent future deterioration.

Using Mild Soap and Water for Dirt Removal

If your challenge coin has accumulated grime, fingerprints, or sticky residues that dry dusting cannot remove, a bath in lukewarm water with a mild, pH-neutral soap is the safest next step. Use a soap like diluted dishwashing liquid (e.g., Dawn) or a conservation-grade soap used in museums. Avoid soaps with moisturizers, fragrances, or antibacterial agents, as they can leave a film. Fill a small bowl with lukewarm—never hot—distilled or filtered water. Hot water can damage certain platings and soft enamels. Submerge the coin and gently agitate the water. You may use your gloved fingers to very lightly rub the surface, but never scrub. For stubborn dirt in recessed areas, a soft-bristled toothbrush dedicated solely to coin cleaning can be used with extreme gentleness. Rinse the coin thoroughly under a gentle stream of lukewarm distilled water to remove all soap residue, as leftover soap can attract dirt. The most critical step is drying: immediately pat the coin dry with a soft, absorbent, lint-free cloth (like a microfiber towel). Do not rub. Then, allow it to air-dry completely in a warm, dry, dust-free environment before returning it to storage. Any moisture left behind will cause spotting or corrosion.

Avoiding Harsh Chemicals and Abrasives

This rule cannot be overstated: never use common household cleaners, polish, solvents, acids (like lemon juice or vinegar), baking soda pastes, or abrasive materials on your challenge coins. These substances are designed for tougher jobs and will irreparably harm the delicate surfaces. Polishes and abrasive cleaners work by removing a thin layer of metal to reveal a shiny layer beneath. This process destroys the original mint surface, devalues the coin, and can remove protective platings, exposing the base metal to faster corrosion. Solvents can dissolve colored enamels, epoxy coatings, and antique finishes. Even seemingly gentle options like toothpaste are abrasive. The damage from these methods is often cumulative and irreversible. A reputable challenge coin maker applies specific finishes and platings that have their own care requirements. Using a generic "metal polish" is a surefire way to ruin that specialized work. If you are unsure about a cleaning method, the safest approach is to consult a professional conservator or the manufacturer directly. When in doubt, do less. A coin with a bit of honest, stable tarnish or dirt is always preferable to one that has been scrubbed into a dull, scratched, or pitted state.

Cleaning Specific Metals (Brass, Bronze, Silver) with Appropriate Cleaners

Different metals require tailored approaches. Understanding the composition of your coin is key. Many challenge coins are made from brass or bronze with various platings (like gold, nickel, or copper).

Brass & Bronze: These copper alloys naturally develop a patina over time. For many collectors, this patina is desirable and should not be removed. For light cleaning, the mild soap and water method is sufficient. For heavier tarnish, a specific brass or bronze cleaner can be used sparingly and only on coins without enamel colors. Apply a tiny amount with a soft cloth, wipe gently, and rinse and dry immediately.

Silver: Silver coins tarnish due to reaction with sulfur in the air. For light tarnish, use a specially formulated silver polishing cloth impregnated with a mild anti-tarnish agent. Rub gently. For heavier tarnish, a dip-type silver cleaner can be used, but it is aggressive and will strip any natural toning. It is crucial to rinse the coin thoroughly in distilled water afterward and dry it completely. Never use a silver dip on coins with antique finishes or any non-silver components.

Clad or Plated Coins: Coins with gold, nickel, or black nickel plating are particularly vulnerable. Stick to distilled water and mild soap only. Abrasives will quickly wear through the thin plating. When you create your own military coin with complex multi-plating, always ask the manufacturer for their recommended care instructions.

Recommended Cleaning Approach by Metal Type

Individual Protective Cases or Capsules

Once clean, a coin's primary defense is its storage. Individual protective cases, often called "air-tite" capsules or slabs, are the gold standard for valuable coins. These are hard plastic cases consisting of two halves that snap together around the coin, often with a foam or plastic ring to hold it securely without pressure on the face. They provide a rigid, sealed environment that protects against scratches, dust, fingerprints, and minor impacts. For challenge coins, which are often thicker than standard coins, ensure you purchase capsules specifically sized for their diameter and thickness. Many challenge coin manufacturers and specialty retailers sell these. The capsule itself can be wiped clean without ever touching the coin inside. For a coin you designed when you decide to create your own military coin, encasing it immediately upon receipt ensures it remains in "as-struck" condition indefinitely. This is the single most effective storage investment you can make.

Display Cases for Showcasing Your Collection

For those who wish to enjoy their collection visually, display cases offer a beautiful and protective solution. Look for cases made from materials that are inert and non-off-gassing, such as acrylic (Plexiglas) or glass with a wooden frame. Avoid cases with cheap felt or foam backings, as these can contain acids or sulfur that promote tarnishing. Opt for cases with a soft, acid-free fabric lining or velvet that is specifically labeled as conservation-grade. The case should seal well to limit air exchange but not be completely airtight unless it includes a controlled environment. Wall-mounted shadow boxes, desktop cases with locking lids, or even custom-built cabinets with glass doors can transform a collection into a striking display. Position the display case away from direct sunlight, which can fade colors and cause uneven heating, and away from high-traffic areas where it could be bumped. A good display case from a reputable supplier balances aesthetics with preservation, allowing you to share your pride without sacrificing the coins' long-term health.

Albums or Binders Designed for Coins

For larger collections or for collectors who enjoy flipping through their coins, archival-quality albums and binders are an excellent option. These systems use clear, inert plastic pockets (often made from Mylar or polypropylene) that hold individual coins or their protective capsules. The pages are then housed in a three-ring binder. The key is to use products specifically marketed as "archival," "acid-free," or "PVC-free." Avoid cheap plastic pages at all costs, as many contain polyvinyl chloride (PVC). Over time, PVC breaks down and releases hydrochloric acid, which will cause a sticky, greenish corrosion on metal that is impossible to remove completely. Archival pages protect against this and allow for safe, organized, and portable storage. You can group coins by theme, branch of service, or year. When sourcing these supplies, many retailers that work with a professional challenge coin maker will also stock appropriate archival storage materials. This method is particularly popular for collectors who trade or bring their coins to shows, as the binder is easy to transport and present.

Controlling Humidity and Temperature

The ambient environment is a silent factor in coin preservation. High humidity is the enemy of metal, leading to oxidation, corrosion, and, in severe cases, the growth of mold or mildew on paper inserts or case linings. The ideal relative humidity (RH) for storing metal coins is between 40% and 50%. Temperature should be stable, ideally between 18°C and 22°C (64°F to 72°F). Avoid storing coins in basements (damp), attics (hot and cold extremes), or garages (temperature swings and fumes). In humid climates like Hong Kong, where average relative humidity can exceed 75-80% for much of the year, environmental control is critical. Use silica gel desiccant packs in your storage boxes, display cases, or safe. These packets absorb excess moisture and can be reactivated by heating when saturated. For valuable collections, consider a dehumidifier for the room or a specialized humidity-controlled cabinet or safe. Stable, moderate conditions prevent the cyclical expansion and contraction of metals and the activation of corrosive chemical reactions, ensuring your collection remains pristine for the long term.

Understanding the Causes of Tarnishing

Tarnishing is a surface discoloration caused by a chemical reaction between the metal and elements in the environment. It is not rust (which is iron oxide); for challenge coins, it is most commonly silver sulfide (black tarnish on silver) or copper oxide/carbonate (the green patina on brass/bronze). The primary catalysts are:

• Airborne Sulfur Compounds: Present in pollution, industrial emissions, and even from materials like rubber, wool, or some paints and cardboard.
• Moisture (Humidity): Water vapor accelerates chemical reactions and can carry corrosive agents.
• Skin Oils and Salts: Direct handling deposits acids that etch into the metal.
• Chlorides: From salt air (coastal areas) or handling with salty hands.
• Acidic Storage Materials: Paper, cardboard, certain woods, and some plastics can off-gas acids over time.

Using Anti-Tarnish Strips or Sprays

For an added layer of defense, especially in challenging environments, incorporate anti-tarnish products. Anti-tarnish strips are small paper or fabric strips impregnated with a substance (often activated carbon or a metallic compound) that absorbs sulfur and other corrosive gases from the air within an enclosed space. Simply place one or two strips in your storage box, display case, or album page holder. They are effective for 6 months to 3 years, depending on the environment, and are then replaced. Anti-tarnish sprays create a microscopic, invisible barrier on the coin's surface. A light, even coat can repel moisture and slow tarnishing. However, use these with caution: test on a less valuable coin first, ensure the spray is specifically designed for collectible metals, and avoid spraying on enameled areas. Some purists prefer not to apply any coating, as it may alter the coin's surface over very long periods. For most collectors, especially those storing coins long-term, anti-tarnish strips placed in the storage container offer a safe, non-contact, and highly effective solution that many professional challenge coin manufacturers recommend for their products.

Regular Cleaning and Maintenance

Preservation is not a one-time task but a consistent routine. Establish a schedule for inspecting and lightly maintaining your collection. Every three to six months, in a clean, well-lit environment, carefully examine your coins in their holders. Look for early signs of milkspotting (white deposits on silver), verdigris (green corrosion on copper alloys), or active red rust on any iron components. Check that desiccant packs are still effective and replace anti-tarnish strips as needed. Perform gentle dry dusting on capsules and display cases. This regular check-up allows you to catch and address small issues before they become major problems. It also deepens your connection with your collection, as you appreciate each piece anew. Documenting your collection with notes and photographs can also be part of this routine, serving as a record of condition over time. This disciplined, attentive approach is the hallmark of a serious collector and ensures that the craftsmanship of your favorite challenge coin maker is honored through diligent stewardship.

Recap of Best Practices for Coin Care

Caring for your metal challenge coins is a rewarding practice that protects your investment and heritage. To summarize the essential guidelines: Always handle coins by the edges, using clean gloves for valuable pieces. Clean only when necessary, starting with a dry microfiber cloth and progressing to lukewarm distilled water with mild soap for dirtier coins. Never use harsh chemicals, abrasives, or polishes. Store each coin in an individual, inert plastic capsule as its first line of defense. For display or larger collections, use archival-quality cases, albums, or binders that are PVC-free and acid-free. Crucially, control the storage environment by maintaining stable, moderate temperature and humidity (40-50% RH), using silica gel and anti-tarnish strips as needed. Conduct regular visual inspections and light maintenance every few months. By following these steps, you create a preservation system that addresses all threats—physical, chemical, and environmental.

Resources for Finding Cleaning Supplies and Storage Solutions

Sourcing the right tools is easier than ever. Start with the manufacturer; many challenge coin manufacturers sell or can recommend specific storage capsules sized for their products. For general numismatic supplies, reputable online retailers like Wizard Coin Supply, Air-Tite Holdings, or Lighthouse (popular in Europe and Asia) offer a vast range of capsules, albums, gloves, and cleaning cloths. In Hong Kong, specialized hobby shops in areas like Mong Kok or Wan Chai may carry basic supplies, but for archival-quality materials, online international retailers often provide the best selection and expertise. For professional conservation advice or to clean a severely damaged or historically significant coin, seek out a professional numismatic conservator. Organizations like the American Numismatic Association (ANA) have directories of accredited conservators. Remember, the small investment in proper supplies from a trusted challenge coin maker or numismatic supplier pays immense dividends in the longevity and beauty of your collection, ensuring that every coin you own or create your own military coin to commemorate remains a source of pride for a lifetime and beyond.