During the war, the public were urged to save old bones as part of the salvage drive.
This article from the Illustrated London News, 2 November 1940, shows how glue and fertilisers could be extracted from the processed bones.

Title	Glue from bones, 1940
Maker	--
Production Date	1940
Format	Magazine
Copyright	--
Holding Institution	TUC Library Collections, London Metropolitan University
Related Objects	Put Out Waste Bones-they make glue for aircraft-poster