Paraffin waxes are separated from crude oil during the production of light (distillate) lubricating oils. These semi refined paraffin waxes are categorized by oil content and the degree of refinement. The crudest versions fall into the slack wax category and contain between 5% to 20% oil. Next on the step of refinement are scale waxes containing between 1% to 5% oil. The highest grade of refinement is the fully refined wax. Fully refined paraffin waxes contain less then 0.5% oil and have been hydrotreated or clay treated to remove impurities and color. The resulting waxes are water clear, odor free, and normally food grade.