Potatoes showing a patch of green are perfectly safe to eat. The substance that causes the green cast is toxic to humans, but only in quantities far greater than found in any potatoe. Just ask Google. We trash enough blemished food in this country to feed a third world nation. It's disgusting.
It is not recommended. It can indicate the presence of a toxin. If you can't peel away the green then best to throw the potato out.
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