Edited***
A very profitable variation of the never-ending treasure chest respawn is to park a character next to:
1)Brokk the Smith alchemy table on the 1st level of Atzel's Fortress. (Alchemy drop confirmed.)
2) Inside the forcefield next Shraddrizzarto, the first Boss in the Cistern.
(Alchemy drop confirmed.)
Billon
Niello
Bronze
Candidum
Corinthiacum
Decorative Zircite
Hepatizon
3) Lord Suth's alchemy table on the 5 level of Atzel's Fortress. (No drops confirmed)
Park your character next to these spots. Log out. Check back in every 20 mins.. Normally alchemy materials. However there is a 10% chance there will be a recipe in the box. Cha Ching!
Much easier to do this than to kill him 100 times.
Try it out.
Please post other sweet spots if you have them.