My grandmother (born in 1936) said that she remembers her mother saving the drippings from cooking meat and donating it to the war effort in the 40s. What sort of things was it used for?
Note - not bacon grease, the fat and oil one gets from cooking beef, or sausage in a pan
They were used in the production of glycerin (a.k.a. glycerine or glycerol). This was in turn used to make nitroglycerine which was used in explosives production for the war.
Any kind of oil whether from rendered beef drippings, fry oil, or bacon fat were interchangeable for this purpose. The program was only partially successful because many households were already reusing the fats in other ways.
Here is Goofy to explain the fat salvage program: http://www.liveleak.com/view?i=061_1381620464