You’ve found a coin. You think it might be valuable. And it looks interesting enough to keep in any case.
Time to clean it up before you take it for some expert advice!
One of the reasons this Mukden Tiger coin became one of the most valuable Chinese coins ever sold is that it was so well preserved. A custodian's job is to maintain and do no harm.
STOP!
If your coin is valuable, cleaning could destroy that value.
Here’s what you should know before you start.
Coin value depends on condition
Condition is one of the key variables in coin value.
And cleaning can change condition. You might think it’s changing it for the better. Sometimes it is, but if you make the wrong choices you can do damage - and “good condition” isn’t always the cleanest and shiniest version of your coin.
Never use these cleaners on a coin
A great household cleaner, but vinegar might do irreparable damage to your coins.
Abrasives are all bad all of the time.
That means toothpaste, baking soda derived cleaners and most proprietary metal polishes should be avoided.
Acid is bad. Vinegar, lemon juice, ketchup, cola… don’t use them.
Don’t use these cleaning tools
Cleaning media, like wire wools, harsh brushes and even overly abrasive clothes must be avoided too.
Fine on a floor, not so good on a delicate gold coin.
Should you clean your coins at all?
Probably not.
Condition is complex and you may be doing damage that you can’t even see with the naked eye if you clean.
Age is also part of the appeal for many rare coins. Signs of age are part of that appeal. Cleaning can wipe them away.
The state of a coin might contain information that helps to date or locate it. If you discover something that may have historic value and you can safely leave it in situ, the archaeologists will thank you.
What should you do with your coins?
Preserving the condition your coin is in is your first priority.
A lot of coin damage is caused by other coins.
Store your coins separately, in acid-free wrappings. You can find these quite cheaply online.
Acid free storage and good labelling is the best start to safe coin collecting.
Coins are more robust than stamps, but they don’t like to be too hot, cold, or humid and should certainly be kept in stable, dry conditions.
If have measuring equipment, you’re looking for 45 to 55% relative humidity and a temperature of around 65-70°F, or 18-21°C- which isn’t far off a comfortable indoors temperature for most people.
Expert advice
You can discover a lot yourself, but you may want to seek out paid expert advice.
Buying rare historic coins today
We buy and sell rare historic coins.
You can see some of our collections here.
