Many vacuum pumps use lubricant oil for seals, and this oil can cause troublesome back migration, oil mist and can make maintenance more challenging. One solution for some of these issues would be the use of foreline or roughing traps, meant to eliminate or reduce backstreaming oil from oil-sealed pumps. However, these usually have room temperature walls, allowing liquid oil to line inner surfaces. If the oil passes through to the system side of the trap, it will become a vapor source and entrance into the system is no longer preventable. In the long run, these traps can create more work- removing traps to check if oil is passing through and additional cleaning and maintenance. Oilless vacuum pumps, on the other hand, are completely clean-running and there are no traps to fiddle with. There is also no oil pollution or annoying smell, and there is no longer the cost and hassle of waste oil disposal. Some other advantages of oil-free vacumm pumps include increased efficiency, reliability, and flexibility.