How Should I remove this Green Patch?

[Laomedan]

Any ideas on how to get rid of the green on this coin?

[awl]

2 questions. Is the green stuff hard and is it elevated from the rest of the coin?

[postvmvs]

It looks to me that the coin was harshly cleaned in lye. Based on the image I'd wager that the "green stuff" is what remains of the original patina and the brown surfaces around it is a result of the chemical reaction involving lye and the bare metal.

[Robert_Brenchley]

Either that or it's the remains of a great patch of the sort of green decay that usually covers a pit.

[Laomedan]

Well this coin came in a lot off of ebay, it was covered with that tan color with the green patches. After soaking in olive oil for about a month the tan scrubed off with a tooth brush, but the green stayed. it is slightly elevated and i can pick off pieces on the edge with a needle. I have never used lye on coins but it sounds bad. Too bad it wasn't green all around that whould have made a nice coin. Should i keep using the needle or is there another way.

[Roma_Orbis]

What you see is the brown primary layer of bronze corrosion; the second layer, superficial, often green (your case) constitutes the patina, which has quite vanished due to some harsh cleaning or bath in any acid. The yellowish layer on top of the brown is what remains of the green layer.

Jérôme

[Laomedan]

So Should I remove whats left of the green? If so, how?

[curtislclay]

I would remove it with a scalpel under the binocular microscope.  It's a lot of work!

[Laomedan]

Thanks for the tip. I will give it a try.