How do you get eggshell coins?

The coins stay inside Egg Heist: you spend them in the Egg Heist Shop on things like talent nodes, and they do little for you anywhere else in the game.

Most of your coins come from the loot you carry out of a run. Extracted items turn into currency either automatically when you exit or when you sell them at the shop. Anything left over sits in your backpack after the heist, and you have to move it to your inventory before you can sell it through the backpack menu's relic section.

The daily and weekly chests are the other steady source, so opening them each time they reset adds up on top of your runs.

What not to sell for coins

Relics and essences are also what you upgrade Egg Heist talents with, and deeper nodes in the talent tree need rarer resources such as pink essence. They are easy to sell by accident, especially from the inventory's All tab. Check what you are selling before you turn talent materials into a handful of coins.

Not settled: The game doesn't use one fixed name for this currency. Eggshell Coins, shell shards, Prismana and Umbrals all refer to it, so it's easy to mix up with Prismana Shell Shards, which you get as rare loose loot and from hatching eggs collected in a run.