Kill a cookie....

I am using setCookie("cookie1", "$form_variable") Is there a command like killCookie? I am finding that my pages are remembering cookies after they are needed. I've looked on php.net, but couldn't find anything. Tris... ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. **********************************************************************