ok, basically go to the mercenary camp, get a solo mission where you have to collect items. once you've collected at least 1 of the correct items, charm the next mob you're going to kill, give it the item you need to collect and kill it.... you'll get the item(s) that you gave it back and finish the mission faster than you think, plus you keep the items so next time you do that mission you only need to kill 1-2 mobs.