The invention relates to the use of an acidic aqueous composition for pretreating cans, wherein an inorganic-organic conversion layer is formed in the course of the pretreatment, said conversion layer, as such, offering an excellent adhesive base for wax which improves sliding of the formed can and for the subsequent coating. The invention relates to a wet-chemical pretreatment method in which a can cylinder is first contacted with an acidic aqueous composition that contains water-soluble inorganic compounds of Zr, Ti, Si, Hf or Ce, and water-soluble polymers comprising carboxyl groups or hydroxyl groups; and subsequently is contacted with an aqueous wax dispersion. The invention further relates to an acidic aqueous composition suitable for the pretreatment method comprising water-soluble polymers selected from condensation products of glycoluril and aldehydes. The invention further relates to a method for producing can cylinders, said method including the pretreatment according to the invention.