A treatment liquid shall be suitably designed specifically for cleaning bacterially contaminated surfaces of bone implants, dental implants or other components contaminated with a biofilm. For this purpose, the treatment liquid according to the invention comprises, as one of its basic constituents, an aqueous solution of an acid which is provided with a metallic salt in such a manner that a conductivity of at least 30 mS/cm, preferably at least 75 mS/cm, and particularly preferably at least 150 mS/cm results.