Why greases must be saved. Introducing two good soldiers of the home front: the housewife who saves her waste household fats and greases, and the butcher to whom she gives this salvaged fat after she has collected at least one pound, strained it through a metal sieve and poured it into a large, wide-mouthed can. Butchers displaying the poster shown here will pay householders for the fat, and sell it to rendering plants thereby turning this valuable material into industrial channels where it will be processed into ammunition for America's fighting men