A microwave processing system is provided wherein the material to be processed is in the form of a web type quantity configuration with a thickness that is small in relation to the wavelength of a particular microwave frequency. The material is passed through the field associated with a plurality of microwave standing waves of the particular frequency, each adjacent standing wave being offset 1/4 wavelength along the direction of movement of the web. A carrier gas removes volatile solvents from the material surfaces. Control is provided for the interrelationship of temperature, rate of movement, flow of carrier gas, and microwave power.