The iron key is used in the Priest in Perilquest. It is obtained by swapping a golden key for it in the monuments in the dungeon. If the key is lost it can be reobtained by killing a level 30Monk of Zamorak and using the golden key on the monument even though there is already a golden key inside. The iron key allows you to get water from the well in the Mausoleum. The key cannot be stored in the steel key ring.