A yellow discoloration on the surface of Cup of Tea, II (Tasse de the, II), 1966, a cast resin sculpture from the Hourloupe series by Jean Dubuffet, in the collection of the Museum of Modern Art, New York, prompted an investigation into the artist's unusual and somewhat complicated casting technique. A description with supporting photographs of his technique can be found in the 37-volume Catalogue des travaux de Jean Dubuffet, edited by Max Loreau. A brief description of the process is included. The extraordinary aspect of this technique is that it provides for the transfer of the original paint layer from the exterior surface of the polystyrene carving to the interior walls of the plaster mold, and finally, to the exterior surface of the resin casting. With this information taken into account, the MoMA sculpture was examined and analyzed. Evidence found indicates that Cup of Tea, II was cast in this way. Samples were taken from the surface and analyzed with IR spectroscopy. A white translucent waxy material found on the surface proved to be a hydrocarbon - likely paraffin. The spectrum of the hard white material of which the sculpture is made, though not definitively identified, closely resembles several spectra for various polyester resin formulations. The discolored material on the surface proved to be polystyrene, left on the surface as a remnant of the method of manufacture. Upon exposure to ultraviolet light, the polystyrene has degraded and discolored. It is easily removable, but, the question has become, should it be removed? The paper concluded with a discussion of the conservation treatment ethics pertaining to this issue.