Buy either a special block-tin, cast-iron, or copper stockpot, fitted with tap and strainer, or select a large, clean iron saucepan. Fill it two-thirds full of cold water, add a little salt, and then all suitable scraps available. During the day keep adding fresh bits, and keep the pot steadily boiling. It should boil from seven to eight hours a day.

Every night empty the stockpot, straining the liquid off into a clean basin. Wash and air the pot next day, remove all fat from the liquid, pour it back into the pot, and either add fresh scraps or those which were strained out of it if there seems to be any nourishment left in them. If the liquid has been too much reduced add more water.

Once a week, or twice in hot weather, restart the pot with everything fresh. If any stock is left, strain it off and boil it down in an uncovered pan for glaze. When the stock has boiled away until only about a third of it is left, it will become dark brown and of a glue-like consistency. It is then ready to pour off in small pots, and when cold will be like a hard, dark-brown meat extract.

Be sure to keep it well skimmed during the boiling. If the glaze is to be kept for any length of time, cover the surface of it with a layer of warmed lard or dripping, and let it set.