John Keegan, the British military historian, writing in “The Wars for North America” mentioned that the butter shortage of WW II still caused him to save, and use, every scrap of butter in the wrapper.
My Mom - now 95 - always scraped the wrapping paper whenever she unwrapped a fresh stick of butter or margarine. That explains that habit.
http://www.ameshistoricalsociety.org/exhibits/events/rationing.htm
World War II Rationing