RECYCLING AND CHARACTERIZATION OF SPENT ENGINE OIL USING TWO STAGES: SOLVENT EXTRACTION AND CLAY PERCOLATION TECHNIQUES. FUDMA JOURNAL OF SCIENCES, [S. l.], v. 7, n. 3, p. 182–185, 2023. DOI: 10.33003/fjs-2023-0703-1836. Disponível em: http://www.fjsadmin.fudutsinma.edu.ng/index.php/fjs/article/view/1836. Acesso em: 11 sep. 2025.