If fat that has been tried out from scraps and drippings needs to be clarified, let it harden, remove it from the container, scrape away and discard any sediment that has settled in the bottom of the cake and melt it by pouring boiling water over it. Boil this mixture thoroughly, strain through several thicknesses of cheesecloth placed over a strainer, and set away to cool. When the fat is cold, remove the solid cake from the liquid. Discard the impurities in the bottom of the cake. If this process is repeated two or three times, a cake of clean fat may be obtained.

If fat acquires, through use, a slightly burned or disagreeable flavor, melt it and for each pound or pint add a medium-sized potato cut in quarter-inch slices. Heat gradually. When the fat ceases to bubble and the potatoes are well browned, strain the fat through several thicknesses of cheesecloth placed over a strainer, and set away to cool. When ready to use, scrape away and discard sediment from bottom of cake. Potato helps to clarify fat as well as to purify it, for the potato is porous and gathers into its pores much of the sediment in the used fat.