I've been killing leprechauns for hours with 0 drops. Without charms I can't complete the quest... Where the hell do I get this!?!?!??!
There's a map which spawns leprechauns pretty quickly and no other mobs are nearby (unless a boss spawns). If you have mobbing skills and/or summons to help you farm, it'd help you get them faster.
not sure if it's higher, but elder wraiths spawn much more than leprechauns do so you will usually end up getting rags quicker