The klim can was a round tin can that formerly contained powdered milk

Powdered milk

Powdered milk is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for...

. Klim cans were approximately four inches in diameter and about three inches deep. Used in WWII, klim cans were supplied by the Red Cross for the prisoners. Klim cans were instrumental in the escape attempt from Stalag Luft III

Stalag Luft III

Stalag Luft III was a Luftwaffe-run prisoner-of-war camp during World War II that housed captured air force servicemen. It was in the German Province of Lower Silesia near the town of Sagan , southeast of Berlin...

. The metal in the cans could be fashioned into a variety of different tools and other useful items such as scoops and candle holders. Scavenged klim cans were used in the construction of the extensive ventilation ducting in three tunnels that lead out of the prison camp. Former prisoner at Stalag Luft III, Charles Huppert became an expert in turning tin cans into tools. Huppert said, "We used Klim tins for everything that we made, because you could cut the ends out, and have a large piece of tin to work with. You can straighten that out flat, and make a...join them together in a locked joint, such as this, and take your wooden mallet and hammer them down. Then you take your backside of a knife and bear down on that, with a lot of pressure on both sides of that crimp, so that the tin will not separate, in order to make the tools that are used in the tunnels: the digging tools, the funnels, and the lamps to give light."