Disable Del tag in comments

I’m trying to disable the ‘del’ strikethrough attribute from the comments section. I commented out the strike in kses.php and it worked. But when I commented out the ‘del datetime’ tag in kses.php, it didn’t work. I also deleted the ‘del datetime’ tag line from kses.php. That didn’t work either. Is there some other file where I can disable ‘del’ strikethrough attribute?