=Scrap Vat.=--A vessel which requires attention and in which the yield in the oil house can be very materially increased and improved by proper handling is the scrap vat. After the vat is melted and the oil siphoned off, the balance or residue in kettle is drawn out of the bottom into the scrap vat, which is located directly under the melting kettle. This kettle should be kept full of hot water at a temperature of about 130° F., and when the scrap is dropped in the oil will immediately come to the surface; this should be skimmed off promptly, for if it is allowed to lie in the scrap vat a bad flavor will result and it will then have to be sold as an inferior grade of oil; but if skimmed as stated this strong flavored feature may be avoided. When through melting for the day, the steam should be turned on the scrap vats to bring them up to a temperature of 190° to 200° F. This will release any fat yet remaining in the scrap, which should be skimmed and used for a lower grade of oil, as it will have a strong flavor. The balance of the scrap is then sent to the tank house, where it is cooked under pressure and the remaining oil taken out. =Seeding or Graining Oil.=--The oil when settled in the clarifiers is passed to the seeding or graining trucks. The seeding truck plays a very important part in the handling of oleo oil and is one of the points where a great deal of trouble can be developed if not properly watched. When the oil is drawn into the seeding trucks there should be no signs of any water. If there is any water left in the oil it naturally settles to the bottom of the seeding truck. The oil usually being at a temperature of 120° to 125° F., and it being three and sometimes four days before it is cooled, the heat held in the oil, together with the water and sediment that may be in the bottom, causes a decomposition and the result is “sour bottoms,” which are very offensive. If any of this sour material has gotten into the press, the stearine will be spotted and out of conditions. The oil will also show it more or less, so that it is absolutely necessary that this particular point be given very close and careful attention. [Illustration: FIG. 56.--OLEO SEEDING TRUCK.] _Advantage of Wood Seeding Trucks._--It has for many years been considered necessary to line the seeding truck with galvanized iron, in fact many of the large melters today are using this style of truck. The seeding truck, however, which gives the best results is a wooden truck (see Fig. 56) without any lining, made of basswood, or whitewood, which are odorless, and can be readily cleaned and kept sweet. The objections to a truck lined with galvanized iron might be summarized as follows: