What to do with lot of Zs copper coins?

Hello Guru!
I need a piece of advice from you.
I've lot of stacks of Zaishen copper coins (not enough to gain 100 gold ones) I've already got all pets
What's the most convenient way to use coins? I'm close to finish my sweet (6000k left) and drunk (3000k) titles but I prefer not to use coins for Creme Brulè or superalcholics.
Sell them? Use them for Balthazars flames or Z keys? Is El fireworks crate still wanted?
Thanks!

Convert 'em to silver coins and then sell them in GToB. You can get anywhere from 1.5K to 2K each for silver coins.

If you're not going to use them for sweets and booze, convert them to silver and buy Lockpicks to work on Treasure Hunter, Wisdom, Lucky, and Unlucky.

at least get all chars have the biggest equipment pack there is (i will later do this)
then scrolls to the deep, urgoz, UW and FoW if doing that, sup/perfect salvage kits when needed, as said lp's can do alot, z keys for zaishen title and/or drops from that chest, who knows, maybe you'll be lucky
normal and elite tomes when you need em

also: EL crates arent really wanted, as they dont give points, and i barely see anyone who likes just to use fireworks in their GH for fun
not to mention the disco ball and normal crates which can also do it... and those party beacons

so its either titles, packs, sell the coins or get tomes for your skills
and maybe you like the new weapon skins? those envoy ones 9i think they're decent, but prefer others )

If you looking for pure profit, converting to silver coins and selling is the way to go.

I am selling most of my coins (often gold coins) for ecto's (i dont care much about the normal items and i already "bought" some heavy equipement bags before the coins became tradeable)... i have many chars and do lots of zm/zb/zv and occasionally zc. So far i was able to buy 4-5 (out of 8) obisidian sets, 2 elite armors for pvp-only chars, panda charmable pet and 15+ tormented weapons by doing this...

Thanks for the replys
Until now I think I'm going to convert in and sell gold zaishen coins.
Is a 10 gold coins for 20 e a reliable trade?

you'll have to use the price check section for that, or look ingame in temple of balthazar

Yes it is... you have to be patient at times, but there are still many buyers (gtob aed).

1 gold coin -> 2e
1 silver coin -> 2k

It might fluctuate at times, but sooner or later you'll find people paying that much, even from a WTB shout.