What is a great farming method for crimson charms?

In Runescape what is a great method to farm crimson charms? I need them for summoning so I can get the pack yak familiar. What monsters should I kill? What are the charm drop rates for this? I consulted the wiki to see what monsters drop them. I want a monster that drops the charms frequently and are not extremely difficult to kill with a level 161 account.

Solution 1:

Waterfiends. The place I kill them at is the Ancient Cavern which you can reach from teleporting to the Barbarian Outpost with a games necklace then diving into the whirlpool, south of the Outpost.

They drop crimsons very commonly (according to the unofficial wiki, 78-79%) and they are weak to bolts.

If you're having trouble killing them, the Vampyrism aura always helps me heal off them while attacking them.

To boost your efficiency, you can also get a Charming imp from Daemonheim for 100,000 dungeoneering tokens. What this does is automatically puts charms into your inventory from a drop. Or if this is not a viable option, you can do the Distraction and Diversion Familiarisation, which can triple your charm drops for 40 minutes.

They also give great combat experience :)