According to this invention there is provided a method of processing material such as organically coated waste and organic materials including biomass, industrial waste, municipal solid waste and sludge, the method comprising: attaching a material container cartridge containing material to be processed to a processing chamber; heating the material in a reduced oxygen atmosphere in the processing chamber to produce gas; channeling the gas from the processing chamber to a treatment chamber in which they are heated to destroy any VOC's therein; recirculating gas from the treatment chamber back into the processing chamber; and in a first mode of operation modifying the moisture content of the gas recirculating from the treatment chamber to the processing chamber by passing it through a second material container cartridge containing material to be processed.