A method for operating a cleaning apparatus, having a trough and a brush disposed in the trough, in a printing press, includes first, second and third steps. In the first step, a cylinder of the printing press is cleaned by the cleaning apparatus, with the brush bearing against the cylinder. In the second step, the brush is moved away from the cylinder, and a level of a liquid in the trough is changed, resulting in the liquid being brought into contact with the brush. In the third step, the brush is cleaned by the liquid in the trough. A printing press for carrying out the method is also provided.