Create a Ghostly Skeleton Key by attaining at least 500 skill in blacksmithing. If you wish to train through pandaren materials, a training project appropriate to your skill level can be learned from Jorunga Stonehoof.
While it is best to learn the properties of simpler metals and work your way up, it is possible to learn how to become a good blacksmith through mastering the various applications of ghost iron for common household objects. If you wish to take this path towards becoming a zen master blacksmith, I can teach you. Whichever way you choose, you will have my respect if you can show me that you can make a ghostly skeleton key.