How do you remove soil from old copper coins with green patina?

[vince76]

Hello guys.
I usually find copper coins with a nice green patina but sometimes the soil is attacked and very difficult to remove it.
Do you have any idea how to remove the soil.

The first are two dirty coins and i tried to clean the big one.



The second is a clean one. I haven't clean it at all.



Thank You

 

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[Loco-Digger]

I soak mine in hot dish soapy water for about 15 minutes and then take a very soft tooth brush to remove the dirt, unless of course it's a coin of high value. Once I have removed all I can with the toothbrush, I let them dry and then dry clean them with toothpicks using a magnifying glass, getting into all the nooks and crannies.

I do not clean key date or high value coins other than to rinse off the dirt.

If the dirt is so encrusted that hot soapy water does not do the trick, they go into mineral oil and soak for about 30 days and then I try to pick the encrustation off the coin.

Some use very weak acids like vinegar or lemon juice. I use lemon juice to clean my modern coins with some salt, using my rock tumbler.

 

[vince76]

I tried the first method Loco but nothing happened. I'm afraid to use the mineral oil because i've heard that it changes the colour of the patina!