The waste cooking oil is widely used in traditional market. The purification of waste cooking oil is very important to avoid a large number of disposable oil, environmental pollution and health risk of oil consumption. Two types of oils, Chicken/Fish-used Oil and Banana-used Oil, have been treated with the powder of skin of Salacca zalacca in a batch method. The optimum condition showed that 15 g of skin powder has reached at two weeks contact time and 3h shaking time. The results showed the skin powder of Salacca zalacca could improve the quality of waste cooking oil by reducing the MDA value and lipid profile (total cholesterol and LDL). FTIR indicated some functional groups which play the role of chemical interaction such as; C=O stretch of aldehydes, esters and saturated aliphatics; N−H bend of primary amines; N−O stretch of nitro compounds; and C−N stretch of aromatic amines.