Delete and *never use* ci_session cookie?

[eluser]oll[/eluser]
I don't know if there's an ignited code for this.
What I did for my website is for being sure to delete everything (I know it's redondant but I'm a bit paranoid ) is :

Code:

function logoff () {
$this->session->sess_destroy();
foreach ($_COOKIE as $key=>$value) {
  setcookie($key,"",1);
  }
}