ctrl+f (aka find service) inside skillnamegrp.dat ---> Find the skill name and then keep the ID
after that open skillgrp.dat : ctrl+f (aka find service) ----> Paste the ID find the line and remove the texture with the icon word included
example
Before:
3 1 0 0 9 40 3 1.08000004 0 S 3 icon.skill0003 0 0 0 a,none\0 0 9 11 0 a,none\0
After:
3 1 0 0 9 40 3 1.08000004 0 S 3 0 0 0 a,none\0 0 9 11 0 a,none\0