A study on using chitosan as a cleaning agent for used lubricant oil has been successfully conducted. Chitosan, a derivative of chitin derived from abundant crustacean shell waste, has notable properties that make it suitable for applications in various fields, including wastewater treatment, food packaging, wound dressing, biomedical uses, and more. Chitosan is also known to absorb oil, making it an eco-friendly adsorbent for oil spill removal applications. This study aims to explore the extent of chitosan’s eco-friendly application in cleaning used lubricant oil, explicitly focusing on removing permanganate content from used oil. Chitosan solution was added to the used oil, and the treated oil was analyzed using FTIR and UV-Vis. The FTIR spectrum, covering a range of 3500-600 cm⁻¹, indicated the presence of chitosan functional groups in the treated lubricant oil, enhancing its environmental compatibility …