A deer's antlers grow out of the skull and become attached to the bone. When the antlers are cut off they are removed by sawing through the skull, with the antlers, and the portion of skull that they are attached to, coming off as a single unit. This portion of skull is referred to as the skull cap. Whether the antlers are to be mounted alone or on a full head mount, the cap must be cleaned of all flesh and dried to keep it from smelling and decaying.
Remove any skin that is still attached to the skull cap. Pull the skin up, starting at one end, and cut it free by slicing through the membrane that attaches it to the skull.
Use the knife and screwdriver to cut and peel away any flesh attached to the underside of the skull cap. Scrape all the flesh off until the bone is clean.
Lay the skull cap in a plastic pan with the antlers facing up. Pour salt on the skull portion. Rub the salt thoroughly into the underside of the skull cap. Make a mound of salt and push the bottom of the skull cap down into it, so that the salt is in full contact with the bone, and then cover the top of the skull with more salt. Leave this to sit for 24 hours.
After 24 hours, pull the antlers out. The salt should be damp with the moisture it has drawn out of the bone. Brush all the salt off the skull cap. Do not wash the salt off, as this will re-moisten the bone and defeat the purpose of drying it out with salt.
Hang the antlers in a high place, such as in the rafters of a garage or shed, safely out of the reach of any vermin. Leave the antlers until the skull bone is completely dry. This can take a week or two, depending on the weather and humidity. When dry, the antlers are ready to be mounted or displayed.