The patented Carbolescer can eliminate both the aerosol and mist forms of oil. It consists of a pleated separator layer, a carbon layer, and a particulate layer. The pleated separator layer removes the aerosol form of oil. When oily compressed air enters the unit, the oil droplets coalesce and run down the filter medium. The collected liquid oil is automatically drained off. The pleated separator filters out oil contaminants as small as 0.01 microns. In addition to the pleated separator, the activated carbon layer adsorbs oil mist. The oil mist is physically retained by the activated carbon granules and as a result, the oil content can be reduced to 0.003 ppm. The final particulate filter layer actively removes carbon dust and maintains the quality of the compressed air.