The most common driers used in mass finishing or vibratory tumbling processes are cob driers. These units are essentially a vibratory finishing bowl with a heating element located in the base of the machine, separate from the vibrating bowl. The heating element heats the bowl, which is filled with ground corn cob media. This cob has been crushed and screened to specific mesh sizes. The heated cob drier provides a great means to dry and to some level, slightly brighten or polish the work piece.