The style of the Auchernack milk carton is known as Tetra Pak and was invented in 1952 by Ruben Rausing, a Swedish designer. He was interested finding a new solution for packaging milk, which until then had been sold in heavy and costly bottles. This type of plasticised cardboard carton is still commonly used today because it keeps liquids sealed in and microbes out. The cardboard is made up of layers of aluminium, paperboard, and polyethylene and folded from a single sheet. It is lighter and cheaper to produce than glass bottles but is difficult to recycle.