_Removal of Hoofs._--The removal of hoofs is to be done by putting the feet in a tank or tub of water. Steam is injected into the water and the temperature raised to about 180° F., where it is maintained for 20 to 30 minutes, or until the hoofs will slip. Hoofs are pinched off and feet passed to cook boxes. Hoofs are usually air dried and selected into white and striped hoofs, the most valuable used and sold for manufacturing. Black hoofs are ordinarily coil dried and ground for fertilizer. The oil is the neatsfoot oil of commerce. _Cooking Shin Bones._--Shin bones should be cooked about eight hours at a temperature of 160° to 170° F. [Illustration: FIG. 62.--HAND HOOF PULLER.] Judgment is to be used in the cooking as the age of the cattle and the hardness of the bone will have to do with the bone appearing “chalky” when dry. [Illustration: FIG. 63.--POWER HOOF PULLER.] _Cooking Feet._--The foot portion resulting in the small knuckles when cooked is cooked separately from the shin bones and oil handled in the same manner. _Skimming the Oil._--The oil rising to the top of the cook vats should be carefully skimmed off with as little water as possible. It should be strained through a fine mesh screen covered with two thicknesses of scrim, so as to take out all floating fibre or floaters. _Skimming and Settling._--Upon skimming deposit oil in the oil receivers, keep the oil under heat at a temperature of 150° F. The settling or sediment should be daily removed at the drain outlet until oil begins to show, since the settling and moisture are sure means of making oil sour. [Illustration: FIG. 64.--REVOLVING BONE WASHER.] _Purifying Oil._--The oil is kept in the containers until ready for purifying. The two receivers are connected together by a common pipe which terminates in a pipe arranged in the form of a cross with a tee connection at each end. Over the ends of this cross are suspended cotton flannel bags of double thickness tied tightly over the tees. The oil is strained through these into the purifier where it is settled for two or three hours. Should any moisture appear it is withdrawn at the drain cock at bottom. Bags should be used once and carefully washed. The oil is then dried out by heating the same through the steam jacket on kettle until it reaches a temperature of about 250° F., at which temperature it is held several hours. The oil is to be stirred occasionally during the drying period. The steam is closed and the oil allowed to settle and cool and is then put in casks. Temperature of oil when drawn into casks, about 80° to 90° F., casks, hard wood, well hooped and of superior quality to prevent leakage. _Neatsfoot Oil._--Obtained from cooking round shin, flat shin, small knuckle bones (being bones from feet) and shin bones.