The object of this study was to evaluate, on a laboratory scale, the use of cerium concentrate for decolorising container flint glass. A particular objective was to evaluate decolourisation using cerium plus neodymium, since this combination has often been mentioned in literature as the "perfect decolorizer". In addition, decolorizing systems using cerium in conjunction with non-rare earth colourants such as manganese, nickel, cobalt, or selenium, were studied. A single soda-lime base glass was used, but total iron levels were varied over the range of concentrations normally encountered in flint container glass . Optimum levels for the decolourisers in each system studied were determined, and the stabilities of various decolourisers were tested by varying melting times, temperatures and redox conditions.
