Lubricating oil in the equipment circulation lubrication system, after long-term use, the pollutants in the oil will increase more and the lubrication function will gradually decrease. When the pollution is serious, it may cause equipment failure. According to relevant information, 70% to 80% of the failures of the circulating lubrication system are caused by oil contaminants. Therefore, removing the contaminants in the lubricating oil and keeping the lubricating oil in use should be taken seriously by the equipment maintenance workers. This article puts forward some rough views on this issue and discusses it with colleagues.