Abstract: Apparatus for treatment of elastomers and polymers has an inner tube of rectangular section in an outer tubular shell. A treatment medium, for example, a liquid mixture of eutectic salts, is circulated by a pump from a reservoir to a manifold and then to the tube to fill the tube apart from its ends. The medium issues from the ends of the tube into the shell from which it drains to the reservoir. Conveyors are arranged to feed an elongate article through the tube. A hot, gaseous wipe is provided by a device. The interior of the shell is filled with gas under pressure through an inlet. A pressurized water cooling system is included.