Abstract: In a pneumatic dryer, a material which gives off an odorous exhaust during drying is dried in a first dryer section by a stream of hot gas, the major part of the spent gas stream being re-heated by the addition of air and burning fuel under pressure to form the said stream of hot gas. The excess spent gas in the first dryer section is passed through an incinerator to pyrolyze the odorous content of the spent gas stream, and the pyrolyzed gases are used to dry a second wet material in a second dryer section and are then passed to atmosphere. The second wet material does not give off an odorous exhaust. In a modified method a wet material which gives off an odorous exhaust when the moisture content of the material falls below a critical value during drying is dried in the second dryer section to a moisture content having a value above the critical value and is then dried to completion in the first dryer section.