Yes, you can clean your coins. ONLY under certain conditions though.
First of all, DO NOT clean your coins unless something is literally harming it, like a corrosive substance.
The most common form of corrosion is ionic corrosion, resulting from chloride contamination. Whether it’s from sweaty skin or the chemical breakdown of aging plastics. There are dozens of cleaning solvents for cleaning coins.
DO NOT USE ANY OF CLEANING SOLVENTS
They all will leave trace chemicals within the pores of the coins that cannot be rinsed off and will eventually cause more corrosion than the coin had in the first place.
Conservation of a coin should only be done when it has an active chloride corrosion in progress.
We are NOT liable for any damage done to your items. Follow instructions at your own risk.
Here is list of items you will need:
Microfiber or soft cloth
Again, do not use any coin cleaners!
Step 1: Ensure the coin is completely dry by placing it under a heated lamp. Each side of the coin should be under the lamp for 15 minutes.
Step 2: Place the coin on a piece of wax paper, and then place it in your freezer overnight. The wax paper prevents the coin from freezing to the frost layer in the freezer. Freezing the coin contracts the metal and embrittles the mechanical bonding of the crud on the surfaces of the coin.
Step 3: Microwave or boil water. You can use de-ionized water, but it is not necessary for this step. Set the hot water to the side until all the boiling stops, and all bubbles stop forming. Bubbles can strip the surface of the coin if they collapse when in contact with the coin.
Step 4: Using a pair of non-metallic spaghetti tongs, take the coin directly from the freezer to the hot water. The rapid re-expansion of the coin from the thermal shock helps to further break the contaminants mechanical bonds to the coin. After holding the coin in the water for 20 seconds, you can remove the coin and gently set it on a clean surface. At this point you can dab the coin with a Q-tip to remove loose contaminants. DO NOT WIPE THE COIN with the Q-tip or any cloth, as the cotton can scratch the surface of the coin.
Step 5. Dab off any remaining moisture, with a microfiber or soft cloth, then place the coin under a heated lamp. Each side should be under the lamp for 15 minutes to fully dry the surface and pores of the coin.
Step 6. Inspect the coin for contaminants and crud. If still present, repeat steps 1 through 5 above. DO NOT ATTEMPT TO FORCIBLY REMOVE ANY CRUD with anything. Even the use of a cut Q-tip or turkey feather can scratch the coin or abrade the coin surface under the crud.
In our experience, minor chloride corrosion (sticky feel and/or snotty light green color) will be fully removed by this process in one or two cycles, without impacting the original patina of the coin. Coins with carbon crud may take 3 or 4 cycles. If they have heavy thick crud, it may take as many as 10 cycles.
In the end, the coin will be much ‘cleaner’ without having used any harmful coin cleaners.