You buy potatoes. You store potatoes. You forget you have potatoes. You remember you have potatoes. You pull them out and their skins are GREEN!!!
So what's the deal with green potatoes? I heard that the green skins are poisonous. Is it true? And why does it turn green in the first place?
The green coloring on the skin is a build-up of a chemical called Solanine. It is a natural reaction to the potato being exposed to too much light. Solanine causes a bitter taste and if eaten in large quantities, can cause illness (you'd have to eat a lot though).
If you find slight greening on your potato skins, simply peel it off. Try not to peel off the entire skin because it contains valuable nutrients and the majority of the potato's fiber. Cut away any sprouts as well since they are also toxic.
So there you have it. Potato skin mystery solved.