Caring for Collectible Coins
Pro Tips on Storage, Handling, and Cleaning
At Coin Photography Studio, we take our responsibility for the coins in our care seriously. Every step we take — from how we store them to how we handle them — is guided by the same professional standards used by the world’s most respected grading services, auction houses, and conservation specialists.
These aren’t just our preferences. They are the universal best practices of the numismatic profession, and we’re sharing them here so you can protect your own coins with the same level of care trusted by experts.
Proper Storage Techniques to Prevent Damage
Keeping coins in the right environment and containers is paramount to avoiding corrosion, scratches, and other deterioration. Experts note that coins are susceptible to moisture, air pollutants, and temperature swings – and that “improper storage can dramatically reduce a coin’s market value, even if the damage seems minor”. Below are professional storage best practices to protect your collection:
Use Individual Inert Holders: Store each coin separately in archival-quality holders to prevent contact marks. For example, use individual coin flips (made of Mylar or other inert plastic), cardboard 2×2 holders, or hard coin capsules for single coins, and coin albums or folders for sets. These keep coins from touching each other and scratching. Avoid tossing coins loose in a box or bag – “never let the coins rub together, as this leads to scratches that diminish the value”.
No PVC Plastics: Steer clear of cheap vinyl coin flips or any holder containing PVC (polyvinyl chloride). PVC plastic can release acidic chemicals over time that form a sticky green residue on coins and permanently harm the surfaces. Instead, use “inert” coin sleeves or hard plastic cases marketed explicitly as safe for long-term coin storage (often Mylar, polyester, or archival polypropylene).
Control Temperature and Humidity: Coins do best in a stable, moderate climate. Aim to store them in a cool, dry place – ideally around 60–70 °F with low humidity (~50% relative humidity). Fluctuations in heat and cold can cause metal to expand/contract or create condensation, and moisture invites corrosion. Use silica gel desiccant packs in your storage area or containers to absorb excess moisture. Also, avoid storing coins in attics, damp basements, or near sources of water and humidity. Consistency is key: your coins prefer an environment that you find comfortable (room temperature and dry).
Limit Air and Light Exposure: Oxygen, airborne chemicals, and UV light can all tarnish or degrade coins over time. It’s wise to keep coins in sealed holders or containers whenever possible to minimize exposure to open air. Direct sunlight can tone or discolour coins (especially those with silver content) through UV radiation. For display, choose cases or frames with UV-protective glass and avoid placing coins in strong sunlight. In short, store coins in the dark, airtight conditions of a safe or drawer rather than on an open shelf.
Use Secure Storage for Valuables: For very high-value coins or gold/silver bullion, consider upgrading to more secure storage. A home safe is suitable for easy access – choose a fireproof, waterproof safe stored in a stable area of your home. Even better, a bank safe deposit box offers secure, long-term protection (ideal for rare coins you don’t need to access often). Professional dealers note that bank vaults provide excellent environmental stability, though remember that the contents aren’t insured by the bank (you’d need your own insurance). In any case, keeping your most precious coins locked up guards against theft or loss. For coins stored beyond easy reach, a set of finely lit, high-resolution photographs offer the perfect stand-in — letting you enjoy every detail without journeying to the safe.
By using proper holders and storage practices, you’ll protect your coins from the main threats: humidity, chemicals, physical dings, and UV light. As one coin dealer put it, storing your coins properly is one of the smartest things you can do to protect their beauty and value for the long term.
Safe Coin Handling Practices
Incorrect handling is a common way that coins get unintentionally scratched, stained, or fingerprinted. Because collector coins derive much of their value from pristine surfaces, it’s crucial to handle them with care. Here is how the pros handle coins safely:
Hold Coins by the Edges: Always pick up and hold a coin by its outer edge (the rim), not by the face or design sides. Touching the flat surfaces with your fingers can leave behind skin oils or tiny particles that etch into the metal over time. A coin handled on its edges will stay free of fingerprints and surface contamination. If you need to set a coin down, place it on a clean, soft surface like a jeweller’s cloth or acid-free paper – never on a rough tabletop.
Keep Hands Clean (Gloves for Special Cases): Make sure your hands are clean and dry before handling coins. Our skin produces oils and sweat that can cause toning, spotting, or even corrosion on coin surfaces. Washing and thoroughly drying your hands helps avoid this. Many professional graders handle most coins with bare hands (clean) because it gives a better grip and feel. Gloves are generally recommended only for particular situations – for example, when handling ultra-high-grade proof coins or very reactive metal coins like pristine copper. Cotton gloves can prevent fingerprints on proof mirror surfaces, but be cautious: gloves can reduce your dexterity. If a gloved hand fumbles a coin, the drop can do more damage than a fingerprint! Some experts note that “most coins do not require wearing gloves to handle” except perhaps high-grade vintage copper pieces, since copper tones easily. The bottom line: use gloves at your discretion for expensive or proof coins, but always handle them by the edges either way.
Support and Protect While Handling: When examining raw (unslabbed) coins, do so over a soft, padded surface or hold them low over a tray. Accidents happen even to professionals – a coin can slip from your fingers unexpectedly. By working over a towel, velvet pad, or similar soft base, you ensure it won’t hit a hard floor or desk if dropped. It’s also wise to only hold one coin at a time. Stacking coins in-hand or picking up a pile of loose coins invites slips and scuffs. Handle each coin individually, then return it to its holder before moving on to the next.
Don’t Push or Wipe Debris Off: If you see a speck of dust on a coin, resist the urge to brush it away with your finger – even that can create a fine hairline scratch. Similarly, never polish a coin with a cloth to “shine” it. Rubbing = scratching in the coin world. If a coin needs a speck removed, experts might use a gentle air blower or rinse (more on cleaning below), but generally it’s best not to mess with it.
Mind Your Environment: Be conscious of what’s around you when handling coins. Ensure the area is well-lit (so you’re not squinting or needing to bring the coin too close to your face) and clutter-free. Avoid eating, drinking, or smoking while handling coins – tiny food crumbs or a droplet of saliva can land on the coin and cause stains or spots. Likewise, your handling area should be free of chemicals or cleaners; even the fumes from household cleaners can settle on a coin and tarnish it over time. A clean, dry, and neutral workspace is ideal for coin handling.
Properly Passing a Coin: If you’re showing a coin to someone else, don’t just drop it into their palm. It’s safest to either use a holder (put the coin in a flip or small plastic case for them) or hand it to them by the edges. Seasoned collectors often train each other – if someone hands you a raw coin, accept it by its edges, not by grabbing the face. You can also set the coin on a velvet pad and let the other person pick it up by the edges. These habits prevent well-meaning friends from accidentally fingerprinting your coin.
Following these handling guidelines will ensure your coins remain free of new marks. Many older rare coins today still exhibit fingerprints or nail scratches made decades ago by careless handling. By using the same careful techniques as museum curators and professional graders, you’ll avoid adding any damage when you inspect your treasures.
Coin Cleaning: Warnings and Professional Guidelines
One of the most emphatic pieces of advice from veteran numismatists is “Do not clean your coins!” Inexperienced collectors often feel an urge to make an old coin shiny or to scrub off tarnish, but in almost all cases this will hurt the coin’s value far more than help it. Cleaning a coin improperly can cause irreversible damage – and even if the coin’s metal looks brighter afterward, collectors will usually consider it a “problem” coin. Below are the key guidelines and warnings from professional coin experts regarding cleaning:
🚫 Think Twice – Usually, Do Not Clean Your Coins. The general rule among professionals is not to clean coins unless absolutely necessary. PCGS (Professional Coin Grading Service) famously urges collectors: “Stop right there, and DO NOT CLEAN YOUR COINS.” While a tarnished or dirty coin might look like a candidate for improvement, cleaning often does the opposite – it reduces the coin’s originality and value. Trained graders can easily detect cleaning. For instance, when coins are submitted for certification, “signs of cleaning can be evident in many ways… abrasive cleaning… can leave the coin with hairlines” (fine scratches) and an unnatural appearance. Such a coin will come back with a “Genuine–Cleaned” or “Details” grade instead of a normal grade, signaling to buyers that it’s been damaged. A cleaned coin is generally worth significantly less than a comparably graded uncleaned coin – major auction houses consider cleaned coins “problem” coins that bring lower prices than untouched examples. In short, if a coin has collectible value, cleaning it improperly will almost always decrease that value rather than increase it.
🚫 Never Use Abrasives or Polish. One absolute no-no is using any abrasive tool or substance on a coin’s surface. That means no scrubbing, no polishing, no wire brushes, no toothpaste, no baking soda – all of these will put microscratches into the metal. Even wiping a coin with a soft cloth can hairline-scratch the delicate surface. Professional graders often use the term “hairlines” for the fine scratches caused by cleaning, and these are a big red flag on a coin. Polishing in particular is disastrous: it might make the coin shine, but it gives an unnaturally glossy look that strips away the original luster. One numismatic expert noted that once a coin’s original surface is stripped by harsh cleaning, it can “never be fully restored or made Uncirculated again.” In fact, polished or “whizzed” coins (buffed with a rotary tool) typically have their value reduced by at least 50–90% versus an original coin. The advice here is simple: do not use any cleaning powders, pastes, or buffers on a coin – ever.
🚫 Beware of Chemical “Dips” and Solutions. Aside from physical abrasives, chemical cleaners can be equally harmful. Many silver coin dips or jewelry cleaners contain acids that strip off tarnish but also eat away a thin layer of the metal itself. Overuse of coin dip can remove a coin’s natural toning and leave a dull, unnaturally white surface (collectors call these “over-dipped” coins). Other chemicals, like vinegar, lemon juice, or ammonia, may remove dirt but can cause chemical reactions that etch the coin or leave residues that lead to corrosion later. For example, experts warn that cleaning solutions can form compounds on the coin that continue to damage it long after the cleaning is “done”. Unless you have very specific knowledge, it’s safest to avoid all household chemical cleaners on coins. (One mild exception is pure acetone, which we’ll discuss below – it’s often used by professionals in certain cases because it doesn’t react with the metal). In general, do not apply unknown chemicals to a coin; you may solve one issue only to create far worse problems.
🚫 Don’t Remove Desirable Patina or Toning. Keep in mind that “bright and shiny” is not always better. Seasoned collectors actually appreciate the natural patina on older coins – for example, the iridescent toning on a silver Morgan dollar, or the aged green patina on an ancient bronze. These natural surface coatings can add character (and in the case of ancient coins, prove authenticity). Removing an old patina can literally decrease a coin’s desirability. In the realm of ancient coins, never strip the patina unless you truly know what you’re doing. APMEX (a major coin dealer) explains that the patina on ancient coins often “developed over time and may help preserve the coin’s condition… Attempts to remove this patina could result in damage to the coin, which will hurt both its beauty and historical value.” What looks like “dirt” might actually be a stable oxidation layer protecting the coin. So if you have an old copper, bronze, or silver coin with toning – think twice before trying to make it look newly minted. Many buyers would far rather have original toning than a cleaned coin.
✅ If You Must Clean, Use Only Gentle, Non-Destructive Methods. There are a few scenarios where minimal cleaning might be warranted – for example, if a coin has active PVC residue (a sticky green film) or is covered in loose dirt from the ground. In such cases, the goal is to conserve the coin, not to polish it. The safest do-it-yourself method endorsed by some professionals is a simple soak in distilled water. Distilled water (or deionized water) can loosen dirt without introducing chemicals; let the coin sit in the water for a while. If absolutely needed, you might swish it gently or use a soft natural-bristle brush while the coin is submerged to dislodge deposits – but do not scrub the coin’s surface out in the open. Another commonly recommended solvent is pure acetone (available at hardware stores – not nail polish remover, which has additives). Acetone can lift organic gunk like tape residue or PVC without harming the metal. Use it in a well-ventilated area and avoid open flames (acetone is flammable). After a soak, rinse the coin with fresh distilled water. To dry, pat it dry very gently on a soft lint-free cloth or let it air-dry on an absorbent surface like a cotton towel. Never rub the coin dry, and never use paper towels (paper can scratch metal). These methods will remove surface dirt or goo with minimal risk. However, remember that even a careful distilled water rinse can sometimes reveal underlying issues (a coin that looks dull after rinsing may have had its luster hidden by grime). So proceed only if it’s truly necessary. If the coin is high-value, you may be better off not attempting even these mild cleaning steps on your own.
✅ When in Doubt, Seek Professional Conservation: For any situation where a coin is valuable and dirty or tainted enough that you feel it needs cleaning, the best advice is to consult a professional coin conservation service. Both PCGS and NGC offer expert conservation/restoration for coins. These services employ technicians with numismatic expertise who can safely remove PVC residue, verdigris, excessive tarnish, and other contaminants without stripping the coin’s original surfaces. Unlike improper cleaning that leaves a coin impaired, professional conservation “reveals a coin’s originality” by carefully lifting away only the damaging substances. PCGS’s Restoration Service, for example, is designed “to stop environmental damage” on coins – addressing issues like PVC residue, dirt, adhesive tape, or spots – using proprietary non-abrasive methods. According to PCGS, they have about 40 different techniques at their disposal, and will choose the right method for the specific coin’s needs. After conservation, the coin is then graded and encapsulated as usual, often with improved appearance but no “cleaned” disclaimer. NGC’s conservation arm (NCS) similarly has been trusted with coins from shipwrecks and museum collections, and is endorsed by the American Numismatic Association. While these services charge a fee, they can be worth it if you’re dealing with a rare coin where any cleaning risk is too high for a non-expert. As a rule: if you’re unsure, let a professional do it – or simply leave the coin as-is.
💡 Final Thought – Original Surfaces Are King: The overarching principle from the experts is that maintaining a coin’s original surfaces and toning is crucial to its value. Cleaning is usually unwarranted and often harmful. Many experienced collectors prefer a coin with natural tarnish or aging over one that has been obviously cleaned, because originality is part of the coin’s story and appeal. So when in doubt, don’t clean it! As PCGS puts it: “Don’t clean your coins yourself. If you take anything from this, let that be it.” Wise words – sometimes the best care you can give a coin is gentle handling and proper storage, and otherwise leaving it alone.
By following these guidelines on storage, handling, and cleaning, you’ll be caring for your coins the same way professional numismatists and conservationists would. That means your U.S. Mint proofs will stay mirror-bright, your world silver coins untarnished, and your ancient coins preserved with their historic patina intact. In coin collecting, an ounce of prevention is worth a pound of cure – so invest the time and tools to store and handle your coins properly. Your future self (and your coins) will thank you, as they remain just as pristine as the day you acquired them, ready to be enjoyed by the next generation of collectors.
Sources
PCGS – Coin Storage Tips
PCGS – How to Handle Coins
PCGS – Dangers of Cleaning Your Coins
PCGS – Restoration Services
NGC – Coin Storage and Care Guide
NGC – Understanding PVC Damage
NGC – Numismatic Conservation Services (NCS)
Heritage Auctions – Coin Care and Handling
APMEX – Ancient Coin Care