During process operation there are many basic principles which should be adhered to in order to operate the mill efficiently. Do you know that a large volume of oil is lost in the sludge water simply because the oil filled cells were not ruptured to release oil? The oil extraction rate (OER) of the mill can be raised quite easily if only certain simple procedures are followed. They are now documented under the code of practice (CoP). They are given in Figure 1 in a consecutive order so that it is easy to comprehend the correct flow from upstream to downstream. There are seven of them. Millers have to depend only on one upstream activity, i.e. good estate practice.