At Coastal Energy LLC, the mechanism of the re-refining process involves the removal of impurities in spent lubricant oil and bringing it back to the initial state which is base oil without additives. Degradation of the lubricant properties is a consequence of the additives being depleted, whereas base oil molecules stay in contact that can be recovered. Re-refining of used oil means conversion of used oil into high-quality base oils by using the acid-clay conventional process or the latest distillation/evaporation technique along with the final polishing stage of advanced adsorption technology or solvent extraction, and, in the case of group II – hydrotreating