Is there a way to empty a previous cookie based on source ip? I need this to be done because of loadbalancing issues.
You could always use Disallow: /cookies in a robots.txt based on the user agent?
Or if you must drop a cookie to the crawlers, as described above by initall, to delete a cookie, simply have it expire immediately by setting expire to some time before the current time. If you specified a domain and path for the cookie, you have to do the same when you delete it: