harryg
Yes, difficult situation but keep in mind that your example is not a high value coin even without the verdigris. If you choose to treat and attempt to address it,
Hi colleague.
Not a single Indian will die under my hands -save all-heal them all, look at my profile picture.
The disease was great, and to leave the coin to ourselves would only be to destroy it.
The rule here is "don't wait", heal and it's really hard for copper.
Yes, the patina is gone and the green disease. I put a coin in natural oil on the light in the window - the patina will jump out like a "fable Phoenix from the ashes"


The green plague is at hand - the coin will go into oil to acquire a beautiful patina. But it will always be "cleaned" with the addition.
Means used:
A small gas burner the size of a lighter has a nozzle of blue high pressure burning gas ( that's the blue flame + special non-flammable pad + magnifying glass)
Rubber gloves, tissue paper and WD-40.
The coin in my hands casts a rainbow of color depending on the inclination, I let it take on a new patina in natural oil.
Long live the Indian. Or did I make a mistake somewhere?
Ivan