ordinary table salt works fine, the stuff without iodine is best. the smallest grain size you can find (coarse is bad). lay your haides out someplace that isn't hot or in direct sunlite, fuzzy side down. trim as much fat as possible before salting. you can never use to much salt so have at it, rub in as much as you can and leave a nice thick coat on the surface. if you've done the paws (like on a bear) down to the first nuckle, make sure you pack these little pockets real good, shove your fingers in and work the salt into all the little groves. this goes for turned ears, lips and the nostrils.
you can never use to much salt! good luck!