Abstract: A method of processing spent ion-exchange resins contaminated with suspended particles, inorganic residues and/or organic foreign matter so as to render the resin ineffective for continued use, by which method this waste material can be processed to produce useful activated carbon particles instead of simply being dumped in a landfill. In accordance with the invention, granular spent organic ion-exchange resin having an ash content of from 5 to 30% is first dried, then carbonized under a substantially inert atmosphere at a temperature of 300 to 900° C., the inert atmosphere containing 0.2 to 4 volume percent oxygen up to 400° C., and finally activated at a temperature of at least 700° C. under a substantially inert atmosphere containing 3 to 50 volume percent steam.