You see strange white marks on your silver coins…
Unfortunately, you’re not alone. It’s a common story. You buy a collection of shiny, uncirculated silver coins and store them away in a safe, dry cupboard – untouched and ready for a rainy day. But after a few months you go back to find they’re covered in ugly white marks. A milky mystery.
Milk spots can appear at any time – from days to years – after a coin’s been minted (or stamped). The problem occurs as the coin’s being made – when it’s a flat, circular disk known as a blank, or planchet.
The blanks are heated and cooled (a process called annealing) to stop the silver becoming too brittle. But the fatal process happens before annealing when it’s being cleaned and degreased with solvents. Sometimes not all of the solvents are removed before the blank’s heated, sneakily imprinting imperfections into the silver. The newly minted coin may look perfect, but the leftover solvent goes undetected and, as time passes, starts to show.
Milk spots aren’t linked to one single minting process, they’re pretty common across every type of coin. From Canadian silver maple leaf to Chinese pandas – these pesky milk spots can be found on silver bars, too.
Magic them away
There are a number of ways to get rid of milk spots. But silver coin cleaning is always been a risky business, causing scratches or abrasions – so be really careful.
- One way is to use anti-tarnish gold and silver polishing cloths. The ones Bleyer uses are produced by Town Talk and are great quality.
- Another method for lighter spots involves a clean, soft-white rubber – making sure there’s no dirt on the coin – and rub it over the mark. The results can be pretty astounding!
- A more extreme method is using baking soda or fabric softener to make the spots disappear. But check out a reliable recipe before attempting this.
- For some really bad coins, a silver dip or chemical solvent might be nesseccary, or jewellery wipes can be very effective in getting rid of marks.
In all cases, seek advice from your dealer on how to treat your specific coin, as any attempts might damage the coin further. Even the pros struggle to remove these stubborn spots sometimes.
What about the value?
You’ll be happy to hear that the value of bullion coins aren’t affected by milk spots. The coin business sees silver as silver, no matter what marks appear on the surface. Although some specialist collectors buy from each other and can be picky if the coins are covered in marks.
But with proof coins (the highest quality commemorative coins), it’s a different story because people who collect these look for perfection, and milk spots can be pretty ugly. However, dealers are often lenient – understanding that it is mostly the precious metal content of the coin that is valuable.
Minters are making changes
To try and stop white spots, companies are taking it back to the beginning, reassessing how they create coins. The Royal Canadian Mint, for example, recently developed MINTSHIELDTM protection, helping to reduce the number of white spots appearing on Canadian Silver Maples. Many other minters are working on new ways to address the milky spot problem, but only time will tell if these new efforts prove successful.
3 ways to get rid of milk spots
- Use an official silver and gold cleaning cloth on your coins.
- Use a clean, soft-white rubber over your coins.
- Try baking soda or fabric softener (research a reliable method first).
- For bullion coins, pick a silver dip or chemical solvent (research a reliable method first).
Our friendly Bleyer team is here to help. Read more about bullion quality and what to expect here. Or if you’d like to talk to a specialist on the phone, call the office on 01769 618618.