I personally do a lot of full skin birds. When I was a kid I used salt because I did not know better.
My choice would be to pick up a box of 20 Mule Team BORAX at your local grocery store, found in the laundry detergent area.
Rub it into the flesh side of your skin after trying to remove all fat. I let mine hang, pinned to a cardboard for about 7 days.
Do make sure you push it down into the wing area after the bone with meat is removed. It works for me far better than salt.