1933 Guinea-Bissau 5 Centavos

Hello,
Bought a few coins recently and this one was in there, what do you think about that spot closer to the rim? is a corrosion?
Guinea-Bissau 5 Centavos KM# 1
The coin in hand is nice.
Thank you for your comments.
2
Comments
So, went and did some search on the net, and yes it is a corrosion, called "Carbon Spots", and no way to get rid of them, too bad the coin is a nice one.
Too bad about the corrosion spot. I doubt if that coin appears in that grade with much frequency.
Aside from the blemish that is a beautiful coin, and one the US Mint could learn from.
I like it anyway. I sure would be tempted to play with it, but proprietary secrets (LOL).
Well, just Love coins, period.
I will end up selling it as-is, the coin came inside of an old 2x2 kraft envelope from the 60s I think, with a sell price of .20cts