So, back "in-the-day" before Blizz nerfed the Potion of Luck, items like Ghost Iron Ore were very commonly found within the Plundered Treasure. Nowadays, these resources can be found either inside Treasures of the Vale (from rare Pandaria spawns) or if you're an Herbalist, and you find a Golden Lotus, you'll get the buff Luck of the Lotus that will allow you to once again loot Plundered Treasure from Pandaria mobs.
