Was doing my ordinary daily run for the Reins of the Blue protodrake.
When i noticed that the mobs that keep spawning 2 every 5sec, gives lovely charms, and these spawn constantly until you kill the boss.
Very easy to farm even for people with lesser gear, and also bott'able without risk of getting killed.
Guide:
Enter utgarde pinacle
Clear or sneak up to the gauntlet at Skadi the Ruthless
Clear the initial mobs in the gauntlet.
Enter room to the left down at the harpoons, and there just keep killing the mobs that spawns every 5s
Lovely charms keeps dropping in
Good luck