http://www.perlmonks.org?node_id=270323


in reply to Re: Removing cookies
in thread Removing cookies

Not setting an expire at all is good for deleting cookies when the browser session ends. Setting expire to a negative value will delete the cookie during the current browser session if it has been set at some other time (or during the current session). Either way, I realized after I posted that the author of this node most likely knows this already, and is only interested in deleting by domain name.