Abstract: In the gas jet wiping of galvanized wire strip or tube the gas jet wiping nozzle and, preferably a reactive gas containment vessel used for modifying the surface coating on the wire, are made in two or more non-annular parts which when abutted together form an annulus. The parts may be releasably held together in their abutted annular form until the wire, strip or tube requires to be rethreaded, then the parts can be separated from one another transversely of the direction of travel of the wire, strip or tube through the nozzle or containment vessel. The threading of the wire, strip or tube through an annular nozzle or containment vessel is thereby avoided.