Indeed, some historians say this is why people call money green: mold sometimes grows on the bread and cheese and mold is green. Of course, that's a fringe the

Indeed, some historians say this is why people call money green: mold sometimes grows on the bread and cheese and mold is green. Of course, that's a fringe theory. The most mainstream one is that the copper coins people used for pennies would develop a patina of verdigris and would look, like the Statue of Liberty, green.