I don't know if this is mentioned before, but after the squirrel - egg nerf I was looking a spot to farm lovely charms and I found this.
Enter Mogushan Palace heroic. After killing first boss, go downstairs and there are endless bats flying by where first mobs stands after you go down.
It will be a lot easier with a balance druid since bats are neutral and you need to hit every single one of them to pull.
Edit: I got 950 charms in 1 hour with my balance druid.
Edit 2: As zj123 mentioned below, I tried it with my monk and Black Ox Statue pulls neutral mobs so a brewmaster monk is better than any other class.