Used Engine Oil (UEO) is the lubricating oil drained from engines, machinery, or industrial equipment after extended use. It contains degraded base oil mixed with impurities such as dirt, metal particles, fuel residues, and chemical additives. Due to its hazardous nature, proper collection, recycling, or re-refining is essential to prevent environmental pollution. Recycled UEO can be processed into re-refined base oil, fuel oils, or used as an industrial feedstock, contributing to sustainabilit