A system (10) for cleaning nipples (126) of milk-producing animals, in which the animals are housed in a milking parlor (24) and the nipples (126) are cleaned or disinfected before starting a milking operation, the system comprising: a source of disinfectant solution (15)； a manual applicator (26) having a housing volume (84) within which one or more scrubbing elements (86) are located to engage a nipple (126) of the milk-producing animal that has been inserted into the volume ( 84) for cleaning； a supply station (14) in fluid communication with the manual applicator (26) and the source of disinfectant solution (15), to supply the disinfectant solution to the housing volume (84) of the manual applicator (26) with a predetermined concentration of chlorine dioxide； a controller (130), in electrical communication with the manual applicator (26) and the supply station (14), which is configured to start the operation of the scrub elements (86) and the supply of the disinfectant solution (15) to the manual applicator (26) as soon as the scrubbing elements (86) are operated； and wherein the manual applicator (26) can operate remotely with respect to the source of disinfectant solution (15), characterized in that the source of disinfectant is a source of aqueous disinfectant solution of chlorine dioxide (15) provided in the room milking, including the source of aqueous chlorine dioxide disinfectant solution an acidified sodium chlorite disinfectant solution (15), wherein said disinfectant solution (15) has a viscosity and / or vapor pressure substantially equal to that of water .Un sistema (10) para limpiar pezones (126) de animales productores de leche, en el que los animales están alojados en una sala de ordeño (24) y los pezones (126) se limpian o desinfectan antes de iniciar una operación de ordeño, comprendiendo el sistema: una fuente de solución desinfectante (15)； un aplicador manual (26) que tiene un volumen de alojamiento (84) dentro del que están situados uno o má
