There should be a tax in everything that you do within the game. 10% is fine.
Example of Zulie Sinks:
Vending 10% tax: 10% gets burned when selling any item in stores
Storage Fee: Increase the storage fees
Refining / Reinforcement: Increase refining & reinforcement prices
Interplanetary Travel: Increase prices of travel fees
Not burning but reduce the amount of zulie being minted by atleast 30% to 50%. (Ex. When I killed Moldie I get 100 zulies, reduce it to like 50 zulies)