The uneaten remains of edible things are sometimes hauled off to be rendered.
In 1984, C.J. Fenton of Alfa-Laval Pty., Ltd, in Lidcombe, NSW, Australia, wrote a report about rendering some of this uneaten edible stuff so that it becomes, again, edible. Fenton’s report [an image from which you see partially rendered here, at the right] begins:
Before describing the processes used for edible rendering, I felt it could be of some advantage to look at the term “Edible Rendering” with the implications and limitations these might impose….