How to Properly Store and Preserve SWITZERLAND / SCHWEIZ 20 Rappen 1962 B: A Conservationist’s Complete Guide to Toning, Oxidation, PVC Damage, and Proper Holders

I’ve seen too many valuable pieces ruined by improper cleaning or storage. Here is how to keep this safe for the next generation.

As a conservationist who has spent decades examining, cataloging, and preserving numismatic specimens from around the world, I can tell you that few things break my heart faster than seeing a historically significant coin destroyed — not by time, but by human error. The SWITZERLAND / SCHWEIZ 20 Rappen 1962 B, struck at the Bern mint, is precisely the kind of piece that deserves careful, informed stewardship. Whether you acquired this coin as part of a Swiss collection, picked it up from a fellow hobbyist, or found it online, the decisions you make today about how you handle, store, and — critically — whether you clean it, will determine whether it retains its numismatic value and historical integrity for decades to come.

In this guide, I’ll walk you through everything I’ve learned about preserving a coin like the 20 Rappen 1962 B. We’ll cover the science behind toning and oxidation, the silent threat of PVC damage, how to choose the right holders, and the eternal debate every collector faces: to clean or not to clean. Along the way, I’ll share insights drawn from years of hands-on conservation work and from the collective wisdom of this community.

Understanding the SWITZERLAND / SCHWEIZ 20 Rappen 1962 B: What You’re Preserving

Mint Origin and Metal Composition

The 20 Rappen 1962 B was struck at the Bern mint — the “B” mint mark confirms this. Switzerland has a long and distinguished tradition of minting excellence, and the Bern facility is known for its rigorous quality control. As one forum member humorously noted, it’s hard to believe a coin with certain surface anomalies could have passed the “gründliche und genaue QualitätsKontrolle” (thorough and precise quality control) in Bern — and yet, anything is possible.

The 20 Rappen denomination from this era is composed of a copper-nickel alloy, which gives it a distinctive silvery-white appearance when fresh from the mint. This alloy is relatively stable compared to pure copper, but it is not immune to environmental degradation. Understanding the metal composition is the first step in understanding how — and how not — to preserve it.

Post-Mint Damage: The “Ring of Death”

One of the most important things to recognize about your 20 Rappen 1962 B is the difference between mint-made characteristics and post-mint damage (PMD). As experienced collector JBK pointed out, the circular mark visible on some examples of this coin is what’s known in the hobby as the “ring of death” — a telltale sign of damage caused by a coin rolling machine. This is not a mint error. It is mechanical damage that occurred after the coin left the Bern mint.

Why does this matter for preservation? Because PMD is permanent. You cannot reverse it, and attempting to “fix” it through cleaning will only make things worse. Recognizing PMD early helps you set realistic expectations about the coin’s grade and value, and it reinforces the principle that conservation, not restoration, should be your goal.

The Science of Toning: Beauty, Value, and the Thin Line Between Patina and Damage

What Is Toning, Exactly?

Toning is the gradual change in color that occurs on a coin’s surface as a result of chemical reactions between the metal and its environment. For copper-nickel coins like the 20 Rappen 1962 B, toning typically manifests as subtle shifts in hue — from bright white to golden, amber, or even deeper shades of brown or blue depending on the specific chemical compounds involved.

At the molecular level, toning is essentially a controlled form of oxidation. Sulfur compounds in the air, chlorine from handling, moisture, and even the materials in which a coin is stored can all contribute to this process. The key word is controlled — when toning develops slowly and evenly over decades, it can create what collectors call natural patina, which many consider aesthetically beautiful and historically authentic. That patina can significantly enhance a coin’s eye appeal and, in many cases, its collectibility.

Natural Toning vs. Artificial Toning

Here is where things get critical for the conservationist. Natural toning develops over years or decades and tends to be gradual, even, and integrated into the coin’s surface. Artificial toning, on the other hand, is deliberately induced — often through exposure to chemicals, heat, or reactive materials — to make a coin appear more attractive or valuable. Artificial toning almost always diminishes a coin’s value in the eyes of serious collectors and grading services.

Key differences to watch for:

• Natural toning: Gradual color transitions, often centered around the edges and radiating inward; colors blend smoothly; the surface remains intact and undisturbed beneath the toning layer.
• Artificial toning: Sudden, harsh color changes; spotty or blotchy patterns; colors that appear “painted on” or sit on top of the surface rather than being integrated into it; chemical smells or residues.

My advice: never attempt to artificially tone a coin. The short-term visual appeal is never worth the long-term loss of value and authenticity. If you acquire a 20 Rappen 1962 B with attractive toning, preserve it as-is. That patina is part of the coin’s history — and it’s what gives the piece its unique character and provenance.

When Toning Becomes a Problem

Not all toning is benign. In some cases, toning can progress into active corrosion — particularly if the coin has been stored in a humid environment or in contact with reactive materials. Active corrosion appears as:

• Green, powdery spots (verdigris on copper-containing alloys)
• Rough, pitted surfaces
• Flaking or scaling of the metal surface
• A “sickly” or uneven discoloration that seems to be spreading

If you observe any of these signs on your 20 Rappen 1962 B, the coin needs immediate attention — but not aggressive cleaning. We’ll address the proper response in the “To Clean or Not to Clean” section below.

Oxidation: The Silent Degradation Process

How Oxidation Affects Copper-Nickel Coins

Oxidation is the electrochemical process by which metal atoms lose electrons to oxygen or other reactive elements in the environment. For the copper-nickel alloy used in the 20 Rappen 1962 B, oxidation is a slower process than it would be for pure copper, but it is relentless. Every time a coin is exposed to air, moisture, or contaminants, the oxidation clock ticks forward.

The first signs of oxidation on a copper-nickel coin are often subtle: a slight dulling of the original mint luster, a faint yellowish or grayish cast, or the beginnings of uneven surface coloration. Left unchecked, oxidation can progress to the point where the coin’s design details begin to soften and its surface becomes rough or pitted. Once that original luster is gone, it’s gone forever — and with it, a significant portion of the coin’s numismatic value.

Environmental Factors That Accelerate Oxidation

In my experience, the following environmental factors are the most common accelerants of oxidation in stored coins:

1. Humidity: Moisture is the single greatest enemy of metal coins. Relative humidity above 50% dramatically increases the rate of oxidation. In tropical or coastal climates, this is an especially serious concern.
2. Airborne pollutants: Sulfur dioxide, hydrogen sulfide, chlorine, and other industrial or household pollutants can react with coin surfaces, accelerating both toning and corrosion.
3. Direct handling: The oils, salts, and acids present on human skin are highly reactive with metal. Even brief, bare-handed contact can leave fingerprint residues that initiate localized oxidation.
4. Proximity to reactive materials: Paper (especially newsprint), rubber, certain plastics, and wool can all release chemicals that accelerate oxidation.

Practical Steps to Minimize Oxidation

Here is my recommended protocol for minimizing oxidation on your 20 Rappen 1962 B and similar coins:

• Control humidity: Store coins in an environment with relative humidity between 30% and 45%. Use silica gel packets or a dehumidifier in your storage area.
• Limit air exposure: Use airtight or near-airtight holders (more on this below) to minimize the coin’s contact with ambient air.
• Handle with care: Always wear cotton or nitrile gloves when handling coins. Hold them by the edges only — never touch the obverse or reverse faces.
• Isolate from contaminants: Never store coins in direct contact with paper, cardboard, rubber bands, or PVC-containing materials.

PVC Damage: The Invisible Killer of Coins

What Is PVC and Why Is It Dangerous?

PVC — polyvinyl chloride — is a type of plastic that was once widely used in coin flips, albums, and storage pages. You may still encounter PVC-containing holders in older collections, estate sales, or budget storage products. PVC is dangerous to coins because it releases chlorine gas over time, especially in warm or humid conditions.

The chlorine released by PVC reacts with the metal surface of coins to form metal chlorides, which appear as a distinctive greenish or bluish-green film. This film is sticky to the touch and, once established, is extremely difficult to remove without causing further damage to the coin’s surface. In advanced cases, PVC damage can cause permanent pitting and irreversible loss of detail — a death sentence for any coin’s eye appeal and collectibility.

Identifying PVC Holders

Not all plastic holders contain PVC, and learning to identify the difference is essential for any collector. Here are the telltale signs:

• PVC flips: Soft, flexible, and often slightly sticky or tacky to the touch. They may have a faint plasticizer smell — a slightly sweet or chemical odor. Over time, they may become cloudy or opaque.
• Non-PVC flips (safe): Made from Mylar (polyethylene terephthalate, or PET), polyethylene, or polypropylene. These are typically crisper, more rigid, and have no odor. They remain clear over time.

Simple test: If you’re unsure whether a flip contains PVC, place a small drop of water on the plastic. PVC will often cause the water bead to have a slightly oily or irregular surface. Non-PVC plastics will allow the water to spread more evenly. When in doubt, replace the holder. The cost of a new Mylar flip is trivial compared to the damage PVC can inflict.

Removing a Coin from a PVC Holder

If you discover that your 20 Rappen 1962 B has been stored in a PVC holder, act quickly but carefully:

1. Do not force the coin out. If the PVC has begun to bond with the coin surface, pulling it free can strip away metal.
2. Gently flex the flip to loosen the coin, and slide it out with minimal friction.
3. Inspect the coin immediately for signs of PVC residue — a greenish or bluish-green film, stickiness, or an unusual sheen.
4. If residue is present, do not attempt to wipe or scrub it off. This is a situation where professional conservation may be warranted. We’ll discuss this further in the next section.

Choosing the Right Holders: Your First Line of Defense

Types of Coin Holders and Their Uses

Proper storage is the single most impactful thing you can do to preserve a coin. For a 20 Rappen 1962 B, I recommend the following hierarchy of holder types, from most to least protective:

1. Slabbed (professionally graded): If your coin has been graded and encapsulated by a reputable service such as PCGS, NGC, or ACS (Swiss grading), the hard plastic slab provides excellent protection. These slabs are made from inert, non-reactive acrylic and are designed to be airtight. This is the gold standard for long-term preservation.
2. Air-tite holders: These are cylindrical, screw-top or snap-fit acrylic holders that come in various sizes to fit different coin diameters. They provide a near-sealed environment and are ideal for raw (ungraded) coins. For a 20 Rappen coin, select the appropriate diameter — typically around 21.05 mm for this denomination.
3. Mylar flips (non-PVC): These are two-piece flips with a clear Mylar window and a cardboard or plastic frame. They offer good protection for moderate-term storage and allow for easy viewing. Make sure they are explicitly labeled as “PVC-free” or “archival quality.”
4. Cardboard 2x2s with Mylar windows: A classic and economical option. The coin is placed between two pieces of cardboard, with a Mylar window for viewing. Secure with staples (not tape — tape can introduce adhesives and chemicals). These are suitable for bulk storage of lower-value pieces.

Holders to Avoid

Equally important is knowing what not to use:

• PVC flips or vinyl pages: As discussed above, these are actively harmful.
• Rubber bands: Rubber contains sulfur and will cause rapid toning and corrosion on any coin it contacts.
• Paper envelopes (standard): Standard paper is acidic and can cause staining and corrosion over time. If you must use paper, choose acid-free, archival-quality envelopes.
• Plastic bags (non-archival): Zip-lock bags and similar household plastics may contain plasticizers and are not designed for long-term numismatic storage.
• Glass-top display cases without climate control: While attractive for display, these can trap humidity and create a microenvironment that accelerates oxidation.

To Clean or Not to Clean: The Conservationist’s Eternal Dilemma

The Cardinal Rule: Do No Harm

If there is one piece of advice I could tattoo on the forearm of every coin collector in the world, it would be this: Do not clean your coins. I cannot stress this enough. In the vast majority of cases, cleaning a coin — even with the best of intentions — reduces its value and damages its historical integrity.

Here is why: cleaning removes the original surface of the coin. That surface — with its natural luster, patina, and toning — is what grading services evaluate and what collectors prize. Once you scrub, dip, polish, or otherwise abrade that surface, it is gone forever. No amount of re-toning or aging can restore it authentically.

Professional grading services like PCGS and NGC will often detail-grade cleaned coins, assigning a label such as “Cleaned,” “Polished,” or “Wiped” that can reduce the coin’s market value by 50% or more. For a coin like the 20 Rappen 1962 B, which may have only modest numismatic premium in circulated grades, cleaning could effectively eliminate any collectible value beyond face value.

When Cleaning Might Be Considered

There are a very limited number of situations where some form of surface intervention might be appropriate — but these should be approached with extreme caution and, ideally, under the guidance of a professional conservator:

• Active corrosion: If a coin is actively corroding (spreading green spots, flaking surfaces), stabilization may be necessary to halt the process. This is a conservation emergency, and the goal is to stop the damage, not to restore the coin’s appearance.
• PVC residue removal: As mentioned earlier, PVC residue can continue to damage a coin if left in place. Gentle removal of PVC residue with a suitable solvent (such as acetone — not nail polish remover, which contains additives) may be warranted. More on this below.
• Removal of foreign contaminants: Dirt, grease, or other non-reactive substances that are sitting on the surface (rather than chemically bonded to it) may sometimes be safely removed.

Safe Cleaning Methods (When Absolutely Necessary)

If you determine that some form of cleaning is truly necessary, here is the only method I would recommend for a home collector working with a coin like the 20 Rappen 1962 B:

1. Pure acetone (reagent grade): Acetone is a solvent that will dissolve many organic contaminants (PVC residue, oils, adhesives) without reacting with the metal itself. It evaporates completely, leaving no residue.
2. Procedure: Place the coin in a glass container and submerge it in pure acetone. Let it soak for a few minutes. Remove the coin and allow it to air-dry on a clean, lint-free surface. Do not rub, wipe, or polish the coin at any point.
3. Important caveats:
   • Use only pure acetone — the kind sold at chemical supply stores. Drugstore nail polish remover contains water, oils, fragrances, and other additives that can damage coins.
   • Do not use acetone on coins with artificial toning, as it may strip the toning and reveal the underlying damage.
   • Do not use ultrasonic cleaners, baking soda, vinegar, lemon juice, commercial coin cleaners, or any abrasive substance. These will irreversibly damage the coin’s surface.

What NOT to Do

To be absolutely clear, here is a list of cleaning methods that should never be used on a collectible coin:

• Rubbing with erasers or abrasive pads (including the infamous “pencil eraser trick”)
• Soaking in vinegar, lemon juice, or other acids
• Using commercial “coin cleaning” solutions
• Polishing with jeweler’s rouge, metal polish, or toothpaste
• Ultrasonic cleaning (acceptable for some industrial applications, but destructive to numismatic surfaces)
• Dipping in acid solutions (this is how “dipped” coins are created, and it removes original luster permanently)

Every one of these methods removes original metal and surface detail. The result may look “shinier” in the short term, but the coin will be permanently devalued.

Building a Preservation Environment: Long-Term Storage Best Practices

Temperature and Humidity Control

Beyond choosing the right holder, the environment in which you store your coins matters enormously. Here are my recommendations for long-term storage of a 20 Rappen 1962 B and similar pieces:

• Temperature: Maintain a stable temperature between 65°F and 72°F (18°C to 22°C). Avoid attics, garages, and basements where temperature fluctuations are extreme.
• Humidity: Keep relative humidity between 30% and 45%. Use a hygrometer to monitor levels, and employ silica gel or a dehumidifier as needed.
• Light: Store coins in the dark. Prolonged exposure to light — especially direct sunlight or fluorescent lighting — can accelerate toning and cause uneven color changes.
• Air quality: Avoid storing coins near kitchens (cooking fumes), bathrooms (humidity), or workshops (chemical fumes). A dedicated coin cabinet in a climate-controlled room is ideal.

Inventory and Documentation

As a conservationist, I always recommend maintaining detailed records of your collection. For each coin, including your 20 Rappen 1962 B, document the following:

• Date of acquisition and source
• Grade or condition at time of acquisition (with photographs)
• Storage method and location
• Any conservation treatments performed (including dates and methods)
• Provenance information — if the coin came from a notable collection like the Swiss Collectors group mentioned in the forum thread, record that provenance. It adds historical value and can meaningfully enhance the coin’s desirability to future buyers.

Photograph your coins regularly — at least once a year — to monitor for any changes in condition. If you notice new toning, corrosion, or other changes, you can intervene early before damage progresses.

Special Considerations for the 20 Rappen 1962 B

Post-Mint Damage and Grading Implications

As we discussed earlier, the “ring of damage” visible on some examples of this coin is post-mint damage from a coin rolling machine. This is not a mint error, and it will not earn any premium. In fact, it will likely reduce the coin’s grade and value compared to a clean example. When evaluating your 20 Rappen 1962 B, assess the severity of any PMD and factor it into your expectations for grading and market value.

If you are considering submitting this coin to a grading service, be aware that PMD will be noted on the label. A coin with significant rolling machine damage may not be worth the cost of grading unless it has other redeeming characteristics — such as an unusually strong strike, exceptional mint-state luster, or an interesting toning pattern that boosts its eye appeal.

Market Availability and Collectibility

The forum thread noted that examples of Swiss 20 Rappen coins dating back to 1885 are available, with the 1962 B being a relatively modern piece in the series. The 20 Rappen denomination has a long and continuous history in Swiss coinage, and the 1962 B is part of that rich tradition. While it may not command the premiums of a rare date or a mint error, it is a historically significant piece that represents Swiss numismatic excellence and the precision of the Bern mint.

For collectors building a type set or a date run of Swiss minor coinage, the 20 Rappen 1962 B is an important piece. Its preservation matters — not just for its own sake, but for the integrity of the collection as a whole. A well-preserved example in mint condition, with original luster and attractive natural toning, will always stand out.

Conclusion: Preserving History, One Coin at a Time

The SWITZERLAND / SCHWEIZ 20 Rappen 1962 B is more than just a coin — it is a small, tangible piece of Swiss history, struck at the Bern mint with the precision and quality that Switzerland is known for. Whether it arrived in your collection with the subtle beauty of natural toning, the honest wear of circulation, or the unfortunate marks of post-mint damage, it deserves to be preserved with care and respect.

Let me summarize the key takeaways from this guide:

1. Never clean your coins unless there is an active conservation emergency, and even then, use only the gentlest methods.
2. Store in PVC-free, archival-quality holders — Mylar flips, Air-tite capsules, or professionally graded slabs.
3. Control your storage environment — stable temperature, low humidity, darkness, and clean air.
4. Handle coins only with gloves and by the edges.
5. Document everything — provenance, condition, storage method, and any treatments.
6. Recognize the difference between natural patina (which adds character and value) and active corrosion (which requires intervention).
7. Understand that post-mint damage is permanent and that attempts to “fix” it will only cause further harm.

Every coin in your collection is a link to the past — to the mint workers in Bern who struck it, to the hands through which it passed, and to the economic and cultural history it represents. As collectors and conservationists, we are the temporary custodians of these objects. Our responsibility is to pass them on in the best possible condition to the next generation of historians, numismatists, and enthusiasts.

Treat your 20 Rappen 1962 B with the respect it deserves, and it will reward you — not just with retained value, but with the quiet satisfaction of knowing you’ve done your part to preserve a small piece of human history.

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