Do not smoke. Smoking slows or prevents bone healing. If you smoke, the graft is more likely to fail. Be aware that nicotine patches slow healing just like smoking does. You may also be told not to take non steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen. These drugs can slow down bone fusion.
Once you've thrown that bit away, get into the ends of the bone and get rid of the last of the spongy bone. I show a file and a rotary rasp bit doing the job. Keep at it until there is nothing which is not bone-coloured in view. Even a tiny patch of darker material needs to be abraded away, and that needs to happen inside and out. 2b1af7f3a8