Most detectorists find a lot of buried coins during their searches, and the dollars can quickly add up. But, some coins may be too dirty to seem spendable. If they are dirtier than what soap and water can clean, there is solution: a rock tumbler.
Please keep in mind that we are talking about the coins that you find that are not of any value above their denomination. If you find old, rare, or silver coins, you shouldn’t try to clean them because it may lower their value significantly. Instead, consult with an expert before you damage that is potentially valuable.
Using a Rock Tumbler to Clean Coins
If you do a search on the internet for how to clean coins, you will find that there are a lot of different methods out there. Some may work better than others, so you should try them out and see which methods you prefer. One such method is using a rotary rock tumbler to clean your metal detecting coin finds. This one is especially simple if you already own a rock tumbler. If you don’t, there are plenty of easy-to-use and inexpensive ones available online.
The simplest method for using a rock tumble to clean your coins is to just drop in your coins, put in a handful or so of aquarium (fish tank) gravel, add a couple of teaspoons (or two quick squirts) of dish soap, and tumble the coins until they are back to the desired appearance.
It’s a good idea to tumble coins by denomination – or at least keep the pennies separate. When pennies are tumbled with other coins, the silver coins may come out looking pink or red due to the color of pennies. You can invest in a tumbler that has double drums which will allow you to tumble pennies in one drum and nickels, dimes, and quarters in the other one, all at the same time.
The aquarium gravel that you use should be white to avoid discolored coins, and it should be the smallest size you can get. This type of gravel is hard enough that its edges don’t rub off easily, and abrasive enough that it cleans even the blackest or rustiest coins.
Final Thoughts about Cleaning Coins with a Rock Tumbler
This disclaimer bears repeating: while using a rock tumbler is great for cleaning the modern coins you find while metal detecting, never use it on collectible, rare, or old coins that are potentially valuable. When in doubt, don’t tumble! Take your find to a reputable coin dealer to learn its value before you make any attempt to clean it. These dealers can spot a cleaned coin and will often deem them less valuable just for that reason.
For your modern coin finds, using a rock tumbler is a hands-off method of cleaning coins that will make your coins clean enough to spend, coin roll, or use in a vending machine.
Jami Olive is a writer, mother and metal detecting hobbyist. She is a regular contributor to the Kellyco Metal Detector Blog