这些污染物包括工厂为防锈、拉拔和机械加工或成型过程中使用的机油、润滑油、动植物油等，在进行涂装前必须除去油类污染物。除油是表面处理重要工序之一。因为油污会使涂膜的附着力降低，还影响涂膜的其他性能，所以必须清洗干净。
These contaminants include engine oil, lubricating oil, animal and vegetable oil used in rust-proof, drawing and mechanical processing or forming processes in factories. Oil contaminants must be removed before painting. Oil removal is one of the most important processes in surface treatment. Because oil stains can reduce the adhesion of the film and affect other properties of the film, it must be cleaned.