Most of us heard of the ‘old trick’ of using Coca Cola to clean up tarnished copper or bronze coins. However, I was curious as to whether Coke could be used to clean silver coins. As a metal detectorist, I have no shortage of old silver coins in need of a polish, so decided to put this DIY cleaning method to the test.
I chose 4 badly tarnished silver coins for the test dating from the Victorian era/Early 20th Century. These coins were black, which I presume that is due to them being found in salt water, after being dropped over a century ago.
The coins silver coins selected for this test were:
- Queen Victoria Sixpence, 1881 (.925 sterling silver.)
- King George V Florin, 1915 (.925 sterling silver.)
- Queen Victoria Canadian 5 cents, date unknown. (.925 sterling silver.)
- Silver Threepence, date unknown.
The theory behind this cleaning method is that the phosphoric acid in the coke, will remove tarnish that has built up on the coin’s surface over the years.
The method is simple. Submerge the coins in Coke for 1 hour, then clean off with water and a toothbrush. Obviously don’t do this with coins of any genuine financial or historic value, as the phosphoric acid could potentially damage the coin if you ‘overdo it.’
Given that my silver coins had been lying in salt water for over 100 years, this was a tough coin cleaning challenge, and I was curious to see if using Coke as a homemade silver cleaner would be sufficient.
The first 2 coins that I chose for ‘cleaning’ were a 1915 Silver Florin, and Silver Threepence. I left them submerged in Coke ‘the Real Thing,’ for an hour, and eagerly anticipated the results. However I was in for a disappointment. After, returning to the coins one hour later, I noticed little difference in their appearance. ???
Not being a defeatist, I decided to dunk the coins in Coca Cola again for a second hour, however even after this second ‘bonus session,’ I once again noticed little visible difference in the appearance of the silver.
Next up for the experiment was a badly tarnished Queen Victoria Canadian 5 cents. It was so badly discoloured that I could not make out the date on it. This coin has had a hole drilled in it, and will have almost certainly once been used as part of a charm bracelet on a Victorian lady’s wrist. As you can see from the above photos, the Coca Cola treatment made no discernible difference to the coin.
I decided to test the Coca Cola cleaning method on one last coin, although to be honest my expectations were not high! The next candidate for ‘cleaning’ was an 1881 Queen Victoria silver sixpence. Like the rest of the coins it was heavily tarnished, and once again the acidic nature of the Coke made little difference to the appearance of the coin.
To summarise, Coca Cola may have it’s place in cleaning lightly tarnished old copper, bronze coins, or even silver that is in reasonable condition to start with, however in my humble opinion it’s not suitable for cleaning heavily tarnished silver metal detecting finds in the condition shown above.
In another article that I hope to write soon, I will reveal more effective methods on how to clean silver that I have already tested and had surprisingly good results with.