How to Prevent Oxidation on Coins?

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Written By Natasha Jones
I'm Natasha Jones, an avid collector of coins, stamps, and paper money.My passion drives me to seek unique finds, from antique shops to international exchanges.I enjoy connecting with fellow collectors through forums and meet-ups, sharing discoveries and insights.

One of the biggest threats to the appearance and value of coins is oxidation. Oxidation occurs when the surface of a coin reacts with oxygen in the air, causing it to develop a dull, discolored layer.

If left unchecked, oxidation can cause irreversible damage to a coin’s surface. Understanding coin oxidation is the first step in preventing it. Coins made from certain metals, such as copper and silver, are more prone to oxidation than others.

Key Takeaways:

1. Understanding the causes of coin oxidation is key to preventing it.
2. Proper storage and handling can help prevent oxidation from occurring.
3. Professional coin preservation services can help maintain the appearance and value of coins over the long term.

Understanding Coin Oxidation

What is Oxidation?


Oxidation is a natural process when a metal reacts with oxygen in the air. This reaction forms a layer of metal oxide on the surface of the metal.

In the case of coins, oxidation can result in a dull, tarnished appearance that can reduce their value and aesthetic appeal.

The degree of oxidation on a coin can vary depending on a variety of factors, including the metal composition of the coin, the environmental conditions it has been exposed to, and the age of the coin.

Effects of Oxidation on Coins


The effects of oxidation on coins can be significant. In addition to the unsightly appearance of tarnish and discoloration, oxidation can also cause damage to the surface of the coin.

This can lead to pitting, corrosion, and other forms of deterioration that can further reduce the coin’s value.

In addition to the physical damage caused by oxidation, it can also impact the chemical composition of the coin. This can change the metal’s properties, such as its conductivity or magnetic susceptibility.

Prevention Techniques

I use several prevention techniques to keep my coins in good condition.

1. Proper Handling


Proper handling is essential to prevent oxidation on coins. I always wear gloves when handling my coins to prevent the transfer of oils and dirt from my hands.

I also avoid touching the surfaces of the coins as much as possible. If I need to move a coin, I use a pair of coin tweezers or a soft-bristled brush to lift it gently.

2. Correct Storage


Correct storage is another important prevention technique. I store my coins in airtight containers to prevent exposure to air, which can cause oxidation.

I also use desiccant packets to absorb any moisture that might be present. It’s important to avoid storing coins in areas with high humidity or extreme temperatures, which can also contribute to oxidation.

3. Cleaning Coins


Cleaning coins is controversial among collectors, as it can damage their surface. However, if done correctly, cleaning can help prevent oxidation.

I only clean my coins and use a mild soap and distilled water solution if necessary. I avoid using abrasive cleaners or tools that could scratch the coin’s surface.

Impact of Environment on Coin Oxidation

1. Humidity and Temperature


Humidity and temperature are the most significant factors contributing to coin oxidation. Humidity refers to the amount of moisture in the air, which can significantly impact your coins’ condition.

When exposed to high humidity levels, coins can develop a greenish or brownish tint, a clear sign of oxidation.

Similarly, the temperature can also play a role in coin oxidation. Extreme temperature changes can cause coins to expand and contract, developing small cracks and other imperfections.

Over time, these imperfections can make it easier for oxygen to penetrate the coin’s surface, leading to further oxidation.

2. Air Quality

Another factor that can impact coin oxidation is air quality. When coins are exposed to pollutants and other harmful substances in the air, they can oxidize more quickly.

For example, exposure to sulfur can cause coins to develop a dark, blackish tint, while exposure to chlorine can cause them to turn green.

To prevent oxidation caused by poor air quality, storing your coins in a clean, dry environment is essential.

This can help reduce your coins’ exposure to harmful substances in the air, which can help slow the oxidation process.

Before you go…

Overall, by taking a proactive approach to long-term coin maintenance and following best practices for storage, handling, and cleaning, I can help to ensure the longevity and value of my coin collection.

Check out my next article: “Does Silver Coin Rust or Tarnish? What You Need to Know.”

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