1. have a 120 druid that has never recruited thisalee crow (optional/more afk: have engineering with a loot-a-rang)
2. switch to gaurdian druid with balance affinity (extra range)
3. do the broken shore campaign up to the part where you meet thisalee in mount hyjal. do not do any more quests in the thisalee chain or else the mobs will disappear
4. mash swipe and loot mobs

all of my estimated 10-15k gold comes from vendoring grays.
you also get shaldorei silk (might be good to stock up for prepatch crafted gear? make and sell bags? idk), nethershard chunks, and dauntless gear tokens

› See More: Farm 10-15K raw gold an hour from infinite mob spawn