Refer to the amn pages for CGI::Cookie or HTTP::Cookie. Following is an excerpt from first.

fetch returns an associative array consisting of all cookies returned 
+by the browser. The keys of the array are the cookie names. You can i
+terate through the cookies this way:

        %cookies = fetch CGI::Cookie;
        foreach (keys %cookies) {
           do_something($cookies{$_});
        }
value()

Get or set the cookie's value. Example: 

        $value = $c->value;
        @new_value = $c->value(['a','b','c','d']);

value() is context sensitive. In an array context it will return the c
+urrent value of the cookie as an array. In a scalar context it will r
+eturn the first value of a multivalued cookie.

expires()

Get or set the cookie's expiration time.
[download]

So try to get all cookies and set their expiration time to not specified (e.g. by setting the value to the number zero), though the cookie will be deleted after session ends. But only the server who wrote a cookie can have access to it :-)

Have a nice day
All decision is left to your taste