After in the oil press the press cake was produced the vegetable oil stores several weeks in an tank. After some weeks are 3 layers of different products.On top the fuel for all accordingly equipped diesel engines. The dark murky oil below is used against dust at dry animal feed.
Try animal feed like grain makes dust and cough at animals. To prevent this some murky oil can be added to the dry feed which binds the dust.
Under the murky oil are materials which can be used as a fertilizer on the fields, or for heating.