08.04.2010: PHP: Delete cookies

PHP and cookie deletion - thats a bloody PITA.
Had to work that out today because a fucked-up WordPress upgrade session - the customers were experiencing strange "don't cheat" messages when trying to log in. Thought I gonna share this with everybody else.
Took me bloody 4 hours to figure this out - at least with Firefox:

foreach($_COOKIE as $strKey => $value) {
  setcookie($strName, 'false', (time() - 3600 * 48), '/', ' ');