Cellulose, usually from cotton linters or wood pulp, is processed to make viscose, which is then extruded into clear, tough casings for making wieners and franks.

They also are shirred for easier use and can be treated with dye to make "red hots". The casing is peeled off after cooking, resulting in "skinless" franks.

Cellulosic viscose solutions are combined with wood pulp to make large diameter fibrous casings for bologna, cotto salami, smoked ham and other products sliced for sandwiches.

This type is also permeable to smoke and water vapor. They can be flat or shirred, depending on application, and can be pretreated with smoke, caramel color, or other surface treatments.