Need some British Copper Help - The Dreaded Green...

rgCoinGuy

What is the recommended treatment for The Dreaded Green on British Copper? It doesn't look near as bad in hand as the picture makes it look, but you can tell it is there. Between 9 oclock and 10 oclock on the Obverse Rim. Any suggestions appreciated!

coinkat

Q tip and I would start with olive oil on that Q tip in that area and if that fails, then slowly move to something stronger...

IloiloKano

Before moving to something stronger than olive oil, bear in mind that such treatment takes time to soften verdigris; however, I believe you will see noticeable improvement with its use, considering the very small area that is affected.

Also, get refined and/or extra virgin olive oil, since it contains a much lower percentage of oleic acid. The percentage of oleic acid is small in any type of olive oil and that is a quite weak acid anyway, but the percentage in refined olive oil is practically negligable at 0.03%.

You might also consider using mineral oil instead, since it doesn't contain any free fatty acids like vegetable oils.

rgCoinGuy

Great thanks guys, I will try some EVOO this weekend!

7Jaguars

There are actually hints of the same verdigris all over the coin, especially in the lettering. Even though it will probably take a polar solvent like the olive oil, do try a bit of acetone and even isopropyl (rubbing) alcohol first & you may get some off with those same Q-tips. I use a tamping action rather than a rub.

MSD61

I had a copper coin with the old green gunk on it and I placed in a shallow glass dish with olive oil and let it soak for at least a week. Then I used a q-tip with a little olive oil and lightly tamped the areas with the verdigris then soaked the coin more and repeated the tamping until all of the verdigris was removed. Then it was to a fast soak in some acetone, let air dry and then into a coin flip.

As a matter of fact it was this coin the image is from my omni coin page:

rgCoinGuy

I see more advice has been given. I think the idea of a soak for a week or two may not be a bad idea to help loosen up the spot and any other virdigris around the letters and devices. I will go ahead and do this today and update in a couple weeks with some after pictures.

I will combine this advice and try this - a couple quick tamps with some acetone on a q-tip, then a couple week soak in some extra virgin olive oil.

At that point I will do some more q-tip tamping, then a final acetone dip. Pics to come in a couple weeks.

Thanks again!