A system and method for providing a filter to prevent contamination of a vacuum pump during use with a freeze dryer. The method comprises evacuating, with a vacuum pump, pressure from freeze dryer monitoring level of oil in reservoir circulating oil between a sedimentary filter and a coalescing filter, and the vacuum pump, whereby a low pressure generated by the vacuum pump enables flowage of the oil collecting condensation and water vapor that evaporates from oil through an exhaust hose collecting, in the sedimentary filter, rust, particulates, and water from oil collecting, in coalescing filter, water vapor and particulate gas to coalesce water vapor and particulate gas into oil, water, and particulates separating, in coalescing filter, oil from water and particulates, whereby oil is rejuvenated injecting clean air into rejuvenated oil and turning the vacuum off and allowing remaining oil in the static system to return to vacuum pump reservoir.
