Coin Conservation On Minor Corrosion And Still Grade Straight

I think that it will not straight grade with those tiny verdigris spots, removed or not.

Treatment with sodium sesquicarbonate is one of normal ways museums use to passivate verdigris. If used here, I think the beautiful may be severely affected, but that is only my guess.

So where does this leave you?

You may try gently removing those tiny verdigris spots with a toothpick dipped in virgin olive oil, but scars left behind under the verdigris spots may well be revealed, and this leads straight back to my original comment that it most probably won't straight grade to begin with.

If it was my coin, I would be tempted to use the toothpick and olive oil, but I would not be looking to having it graded. To clean or not to clean? You know my answer, but the best decision is still up to you.

Verdigris can affect other coins. For this reason, it should be enclosed in a snap lock hard acrylic capsule, so it can still be included in your collection.

Sel has some good points...the verdigris probably has eaten into the coin itself...I think you should try and remove it, whether you leave it in olive oil for a time and then gently pry with a tooth pick...or you just apply the olive oil to the spot and then use the toothpick. The olive oil should sit on the spot for a period of time to allow for penetration into the verdigris. I think it will grade strait once the verdigris is removed...my experience has shown that a darker area remains.

KK

Problem with lumpy verdigris spots is that they eat into the substance of the coin in much the same mechanical way as rust eats into steel or iron, and leaves a scar underneath, when the powdery surface is removed.

That is why I fear that this coin will not straight grade, and why localized picking with olive oil and a toothpick is probably a better way to go in this case. Most of that beautiful patina could remain, with this approach.