Carbonates, and particularly sodium carbonate, are removed from cyanide containing plating baths by taking from said cyanide containing bath at least part of its bath liquid; stirring and cooling in a cooling container the token liquid while in the metastabile state until crystallization of the carbonates occurs; separating the crystallized carbonates from the liquid; and leading the residual liquor back to the plating bath. Preferably, the quantity of bath liquid taken from the plating bath and the moment of this taking are chosen so as to bring the carbonate content of said plating bath, after leading the residual liquor back to it, to a carbonate content of 25 to 45 grams/liter, and the cooling is continued until the exothermic reaction, which is caused by the liberation of the heat of crystallization, starts, and thereafter the mixture is still held for 2 to 4 minutes at 0.5.degree. C. to 1.degree. C. below this starting temperature. The method is useful for all kinds of cyanide containing baths and provides essential technical, ecological and economical advantages.

A bath for electrodepositing gold utilizes, as the essential ingredients of its electrolyte, salts providing the tartrate radical and the carbonate radical. The bath will have a pH value ranging from approximately neutral to highly alkaline, and adjustments to lower the pH will most advantageously be made utilizing tartaric acid. The bath operates with relatively low gold concentrations, and is capable of producing highly pure deposits and highly desirable alloy deposits; it is especially well suited for semi-conductor industry applications.