Described herein is an aqueous composition for removing cryolitic deposits from plants or parts of plants which serve for the conversion treatment of metal surfaces, said composition including a) at least one mineral acid, and b) at least one dicarboxylic acid of the formula HOOC—(CH2)x—COOH, where x is 0 to 3 and no borate-containing compounds have been added to the composition. Also described herein is a corresponding method for removing cryolitic deposits.