What are Milk Spots?

Milk spots are white, milky marks that can appear on the surface of silver coins and bars. These marks resemble dried milk and can vary in size and shape. Milk spots can occur on both bullion and proof-finished coins, but they are more commonly found on silver bullion coins with a purity of 999.0 or higher. They are rarely seen on older coins with alloys.

Cause of milk spots

The cause of milk spots is not confirmed, although it is widely believed that they may form during manufacturing as a result of chemicals used during the minting and annealing process. However, multiple factors may have an impact, including the way the silver reacts with contaminants in the processing, handling, and storage of the coins. Milk spots can appear on silver coins days, weeks, months, or even years after the coins are minted.

Preventing milk spots

There is no definitive way for silver investors to prevent milk spots. However, storing and handling coins wisely can help. Good quality encapsulation within a container that limits the metal’s exposure to the air and elements can prevent premature discolouration. But if milk spots are developed during production, some coins may still develop them eventually.

Efforts to reduce milk spots

Milk spots are common and not limited to a single mint. The Royal Canadian Mint has developed a patented technology named MINTSHIELD™ to reduce the appearance of milk spots. The technology claims to tackle the root cause of white spots and significantly reduce their occurrence for years.

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1oz Canadian Maple Leaf Silver Coin 2023

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All silver maple leaf bullion coins dated 2018 and later are now protected with MINTSHIELD™, and this process appears to have reduced the occurrence of milk spots in silver Maples. The Perth Mint has also taken steps to reduce airborne particles affecting the areas where coins are produced.

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1oz Australian Kangaroo Silver Coin 2023

We sell 1+ £32.03 20.66 20,66 20.66 20,66 20.66 20,66 20.66 20,66 32.03 32,03 31.91 31,91 31.67 31,67 31.31 31,31

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Impact on coin value

Milk spots do not affect the resale value of a silver bullion coin as these coins are valued based on the weight of the precious metal content. However, collectors of proof coins may be more concerned about the appearance of milk spots as these coins are often purchased at a higher price due to their numismatic appeal.

2024 Coin

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1oz British Britannia Silver Coin

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Removing milk spots

It is not recommended to attempt to remove milk spots from a coin. If you do, it could lead to damaging the coin and replacing the spots with small scratches that could worsen its appearance. Some collectors have used a silver polishing cloth or a clean, soft white pencil eraser, while others have tried a chemical “silver dip” that removes a thin layer from the surface of the silver item. However, these methods carry the risk of damaging the coin and are not recommended.

Although milk spots are a common occurrence among silver coins, some collectors view them as further proof of the authenticity of the silver. It has been a hot topic of discussion among bullion investors and dealers worldwide for years. While some mints have attempted to reduce the occurrence of milk spots, it remains uncertain whether they will eventually be eradicated.