Use the Control Enemy glitch to have a monster with a flashing green "spoils" item in its inventory take the item you want restored from Supply. After making sure that your item is on the bottom of the list and is flashing green as if it were spoils, kill that monster. The monster will drop your item, however it will be totally new.
This trick can also be used on gorgon eggs, but the first item on the list will dissapear, and you must trade with them again after they hatch to regain the item. This glitch can even restore the Dragonstone.