I've just redesigned one site and it realised that returning visitors will have problem with it. In previous version, visitors were able to select number of posts to be displayed and by default it was 10. Now, by default it's 20, however, if a returning visitors come to a site he/she will see only 10 because there's session cookie (PHPSESSID) left in a browser - exiting browser doesnt help. Only way to see 20 posts is to clear browser's cookies. Also, it seems there were no expiration times.My question is: can I force all cookies to reset for returning (or all) visitors? How to achieve that?Your help is much appreciated, I'm stuck.