To make use of this glitch you must have reached Skyhold and unlocked Crestwood on your map table. Travel to Crestwood and locate the village. There is a boarded up and locked house there.

To gain access to it you must:

1) Drain the lake and close the fade rift there
2) Have the Deft Hands perk.

After entering this house you will find a bag of loot on the floor along with a chest off to the side. Selectively loot the bag. It will have an "amulet of power" for your inquisitor in it along with atleast one other item. Take the "amulet of power" and leave atleast one item in the bag. This can be done with the chest off to the side as well. Now you exit Crestwood then return. There is a quick travel point in the village so you don't need to travel far after returning. Go back into the house and selectively loot the bag and chest again. the "amulet of power" has respawned and there are new items in the chest.