Question about Copper Zaishen Coin!

I've just started to do those Zaishen Mission in the Great Temple of Balthazar and currently I have 20 Zaishen Cooper Coins . So how do you spend them? I've searched on GW Wiki , and there it says that they can be used for "different goals" , but on Wiki says only in the Zaishen Menagerie.
PS : Sorry for my english!

http://wiki.guildwars.com/wiki/Zaish...ector_overview

Check the line of NPCs in the temple where you get the zaishen quests.

first 3 give the quests the next along rewards your success with coins now check out the last 3 on the right.

Copper coin rewards then silver then gold, There are some good rewards if you can get enough coins.

Ok. Thanks guys!