​​City Dairy Toronto 

Milk Bottle Rationing
Many raw component materials were required for war production.​ Soda Ash used in glass manufacture molding was also used in aluminum airplane production.  Dairies made a patriotic and economically essential appeal for milk bottle return from all sources in a time of glass shortage. Glass was rationed and not available to produce replacement milk bottles. Dairies were encouraged to continue to use and recycle their existing milk bottle supply. Milk bottle hoarding common right from the milk bottle's introduction now became a greater liability to both the dairy ownership and the war effort.

    Toronto Star April 30 1942