An improved aqueous acidic trivalent chromium electrolyte and process for increasing the tolerance of such electrolytes to the presence of deleterious contaminating metal ions which normally progressively increase during commercial operation of the electrolyte ultimately resulting in chromium electrodeposits which are commercially unsatisfactory due to the presence of streaks, clouds and hazes in the deposit. The improved composition contains controlled effective amounts of thiazole and benzothiazole compounds which are effective to mask the adverse effects of such contaminating metal impurities and which also enhance the codeposition of such metal contaminants on the parts being plated thereby reducing, and in some instances preventing the progressive accumulation of such contaminating metal ions in the electrolyte. The invention further encompasses the process of rejuvenating trivalent chromium electrolytes which have been rendered deficient in their ability to deposit satisfactory chromium platings by a controlled addition of such additive agents followed by electrolyzing of the electrolyte to progressively reduce the concentration of contaminating metal ions to a level in which satisfactory performance of the electrolyte is restored.
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