An improved suction nozzle for removing raised edge portions of coated layer formed on flexible substrates such as photographic film, pre-sensitized plate, or magnetic tape. The suction nozzle has a dual pipe structure with a cleaning liquid jetting outlet and a cleaning liquid sucking inlet at one end thereof. The jetting outlet is offset from a longitudinal axis of the nozzle and forms an angle of 30.degree. to 85.degree. with respect to that longitudinal axis. The sucking inlet is located along the longitudinal axis.