The pus content is usually greenish, stained with blood, and contains strings of fibrous tissue and Necrosed matter.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
When the probe touches Necrosed cartilage it will feel like a piece of dry leather or partially softened wood.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
However, I discovered no Necrosed bone by so doing.
"Report on Surgery to the Santa Clara County Medical Society"
Joseph Bradford Cox