This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Pieces of woollen cloth and shredded portions called shoddy are valuable organic manures, being chiefly valued for their nitrogen. This varies from 2 to 13 per cent, according to the purity of the wool from which the shoddy is obtained. As it liberates its nitrogen slowly, shoddy is regarded as a good manure for Hops, Vines, Roses, etc. Besides wool and shoddy all waste cloth refuse might be converted into a manure. It should be placed in layers and covered with soil, and when thoroughly decayed may be spread over the soil as a topdressing. The soil prevents the escape of any ammonia gas generated in the process of decomposition.
Hair, Feathers, Skin, Leather Waste, Greaves may be associated with wool waste and shoddy as manures. They all contain appreciable quantities of nitrogen, and when thoroughly decomposed and matured by mixing with layers of soil, they constitute valuable organic additions to the soil.