Just to add some clarity on these summoned coffin bottles, since I could not find a description anywhere as to how to use them, what you do is summon a coffin bottle. It takes up a slot in your inventory so make sure you have room for it.
Then you open the coffin bottle (which is a 10 slot container) and fill it with 10 single doses of your chosen poison (must be a PoP poison, the ones that proc for 20 minutes or so), then click "combine".
Wallah! You now have a single bottle of poison that contains 10 doses in it, plus you get back all 10 Advanced Poison Vials that you originally made the single dose poisons out of. That in itself makes this very worth questing for.
Qlarq Qent
73 Rog, Luclin Server