You shouldn’t clean coins if you can avoid it, as the process can damage them. If you buy gold coins from Golden Eagle Coins then they’ll probably be sealed in plastic cases anyway, which keeps them safe. If, however, you find some coins with your metal detector or you buy some at a coin show, then as grubby as they may look, it’s best to leave them alone. If you clean metal coins the detergent and chlorine can cause reactions on the surface which can lower their value.
Why might you need to clean coins?
If you’re helping a young coin collector start off their collection and they’re looking at coins that are still in circulation then it’s a good idea to give them a clean. Realistically, their mint finish has long gone and been replaced by a roughened surface that may be harbouring lots of bacteria and fungi.
Here’s how you do it
You need to wash your hands first to remove grease and small dirt and grit particles that could make things worse. Then you should put a clean, dry towel on the work surface to catch any dropped coins and to provide a safe drying spot.
Then fill up a soft, clean plastic container with warm water from your tap and add a tiny squirt of dish-soap. Don’t use a glass, metal or porcelain container as the hard surfaces might damage the edges of the coins. Whatever you do, don’t use harsh detergents or abrasives.
You need another water bath as well, for a final rinse. It should also be a soft plastic container and if you have any distilled water, then use it.
Cleaning the coins
You should clean only one coin at once by dipping it into the detergent mixture and then rubbing it between your fingers and thumb. If you see any dirt you should gently persuade it outwards and over the edge of the coin. Make sure the coins stay separate so they don’t scratch each other.
Rinsing the coins
You rinse coins by running warm tap water over them to start with and shaking the coins under the stream – don’t rub them!
Then, if you have any distilled water, use it for the final rinse as it’ll remove any last chlorine traces as well as any dissolved salts. Once it’s out of its bath, you should only hold it by its edges to avoid leaving imprints on the faces.
Drying your coins
Hopefully, if you used distilled water as a final rinse, then there’ll be no dissolved minerals in the water droplets left on the coins. If you used tap water, there will be, so use a clean, lint-free cloth to wick away any remaining droplets before they dry, leaving behind mineral deposits.
Repeat this process with your other coins, making sure that you change the washing water when it starts to look cloudy. If you have to soak some of the coins to loosen dirt deposits, then do this individually, because if coins touch each other they can cause damage.
Once they’re dry you can store them
Once the coins are 100% dry you can store them. You must wait, as putting them away when they’re still damp can lead to corrosion.