A muffler, scrubber or chemical reactor device for utilization with combustion engines to aid in the removal of impurities from exhaust gases, comprising a housing having a packing therein, an inlet line to said housing for conducting the exhaust gas from said engine thereto, a construction such as a venturi within the inlet line through which exhaust gas will pass, means for aspirating a reactant material into the exhaust gas near the venturi throat and for utilizing the thermal energy of the exhaust gas for liquefaction of materials where needed, an outlet from the housing, and a cooled bypass line ahead of and around the orifice or venturi to provide temperature and pressure control in and across the device.