Problem deleting cookies

[eluser]codelearn[/eluser]
Hey guys,

I'm having a problem deleting cookies using the CI cookie helper. I'm getting the following error in my error log when I use

Code:

delete_cookie("outreach-score");

PHP Fatal error: Call to undefined function delete_cookie() in /home/etc/etc

I am loading the cookie helper, so that doesnt seem like the problem.

Thanks!