Abstract: Deoiling of slack wax or other similar wax composition is accomplished while the wax is confined in a series of cells which are spaced apart by only one-sixteenth to one-half inch and which are vertically or otherwise disposed for drainage along the surfaces thereof from an upper margin to a lower margin. The spaces between the plates are filled to a depth of 4 to 24 inches, preferably 6 to 12 inches, with wax in the melted state while the spaces between the plates are closed off at their lower margins by a body of liquid, preferably a body of the wax, that is of substantial depth underneath the lower margins of said plates and is maintained in contact with the lower margins of the plates. The temperature of the plates is then lowered by lowering the temperature of a temperature-controlling fluid such as water that is flowed through a multiplicity of conduits that traverse the plates in thermally-conductive relation therewith with concomitant solidification of the wax between the plates.