PURPOSE: To easily control an electrolytic silver stripping soln. without using a cyanide compd. and to stably use the soln. by using a specified hydantoin compd. as a complexing agent.

CONSTITUTION: At least one kind between the hydantoin compds. shown by formulas I and II is incorporated by about 10-300 gel into an electrolytic silver stripping soln. as a complexing agent. In formulas I and II, R1,...R5 and R5' are hydrogen or 1-5C alkyl or alkanol group, respectively. The soln. of this composition is used at pH 4-14, 10-90°C and about 0.5-10A/dm2 current density. Consequently, the operating condition is widened, the bath is easily controlled, and the equipment for controlling the soln. is simplified. Potassium hydroxide, sodium hydroxide, potassium chloride, potassium phosphate, etc., are used as a buffer soln.