A process and a system for cleaning excess aluminum from coating baths, e.g. anodization bath solutions, so that they can be reused in an effective manner is provided. The process comprises first passing a portion of the anodization bath solution having excess aluminum through a strong acid cation exchange column in a Na+ form, allowing the effluent to age thereby precipitating cryolite from the effluent; removing the precipitated cryolite from the effluent and then passing the effluent through a strong acid cation exchange column in the NH4+ form, in a preferred embodiment back through the first column, to restore NH4+ to the anodization bath solution and then adding the effluent back in to the anodization bath solution.