Abstract: A vapor degreasing open topped defluxer is disclosed in which cleaning solvent vapors are generated by boiling a liquid solvent in an open topped tank with the parts to be cleaned inserted therein through the open top. The open topped tank is formed from plural upright sidewalls connected to a bottom wall. Heating elements disposed in the tank bottom vaporize the solvent such that the generated heated solvent vapors rise above the liquid solvent to contact the parts to be cleaned and dissolve the grease on the parts. A condenser coil supported within the tank above the liquid solvent condenses the solvent vapors and defines an upper limit or vapor line of the solvent vapor zone located above the liquid solvent and below uppermost edges of the upright sidewalls. The light rising solvent vapors have a natural tendency to rise upwardly out of the tank by following a convection flow path generally along the inner surfaces of the sidewalls and upwardly past the uppermost edges thereof.