It's going to be difficult since this server has been around for quite some time so the amount of Cegels in the game has probably reached a staggering amount. At the moment, I think think the Developers could offer a lottery game, similar to Loot Boxes, and an attempt will require a big sum of Cegel for a chance. Think of it like doing a Grabbit roll, but you use Cegel instead of real cash. As for the prizes, they could be cosmetic items like costumes and wings along with a few consumables and a few not-so-OP gears. Some of my other ideas:

•Guild houses -- Will require Cegels to make, but every Guild can have their own. This can be set on another location, like an instance dungeon, so players won't clutter the map. The furniture will also require Cegels to purchase.
•Weapon and Armor crafting -- Items and catalyst require can be both obtained from monsters and and can bought from crafting-specific NPCs.
•GM auctions -- GM's could auction an exclusive item. Like a weapon where they can place your character name along with the weapon for bragging purposes.