Abstract: An anti-slagging apparatus for a furnace viewing system removes slag build up deposited on a closed circuit television camera lens tube by occasionally releasing a blast or large volume of air through specially designed ports surrounding the tube containing a furnace viewing lens system. The anti-slagging apparatus comprises a double walled cylindrical tube extending through a wall of a furnace for housing a lens tube assembly. An end plate is positioned at the furnace end of the tube and has formed therein a plurality of ports or openings, with each port being directed outwardly at a 30.degree. angle with respect to the axis of the tube assembly into the furnace and with each port being connected to the space formed between the double walled tube. A source of air is provided to the ports from a supply tank, which in turn is connected to a source of air pressure, such as a compressor, or a shop supply. A quick acting, high volume solenoid valve connects the air tank to the tube.