When My CE is Full then what can i use it?it said here can claim?if can where?

Crystal Essence is used in your soul development. Near the top left corner by your HP/MP bars is this blue circle icon. Click it and it will show the souls along with whats needed when you click the dots. Each soul upgrade requires an amount of essence.
Essence is also used in your pixie upgrades after you rebirth.

If you want to know more about soul, check out this guide
http://www.aeriagames.com/forums/en/viewtopic.php?t=1579731
C: hope i helped!