The used oil regeneration using extraction technique has been widely known as one of the cheapest and most competent processes. This research study the effect of activated clay treatment by nitric acid .The effects of some important factors such as acid concentration and contact time were studied on natural clay. The used oil treated by using solvent mixtures, (xylene+butanol+methanol) at solvent: oil ratio 3:1 followed by bleaching on activated alumina and activated clay adsorbent material to generate base oil. The characterization and physico-chemical properties show that the refined oil adsorbed by activated clay has good properties by comparing to activate alumina.