do you know why some butter is wrapped in paper, and some in foil?

here in the US, unsalted butter is typically wrapped in foil, while (the more common) salted variety is wrapped in waxed paper. the salt in butter acts as a preservative, protecting against spoilage from light, among other things. unsalted butter, which is used more in baking, is wrapped in foil to minimize light exposure and prolong its life.

--dan.