Dry them out. I dry mine first in the freezer, and then cut the bone on both sides of the spur. Then pop out the marrow from the leg bone. Then I plunk'em in hot soapy water for a few hours.Rinse & dry, and let set for a few days to completely dry out.

Then you can string themonto a leather shoe lace which is strung through the brass of a turkey load, that is stuffed with the end of a turkey beard. I saw the pix of this type of set-up in either a Turkey Call or American Hunter magazine.