public function clearCache() {
self::$adminsByCatid = array();
self::$adminsByUserid = array();
self::$moderatorsByCatid = array();
self::$moderatorsByUserid = array();
self::$instance->loadAdmins();
self::$instance->loadModerators();
// Store new data into cache
$cache = JFactory::getCache('com_kunena', 'output');
$cache->store(serialize(array(
'ac'=>self::$adminsByCatid,
'au'=>self::$adminsByUserid,
'mc'=>self::$moderatorsByCatid,
'mu'=>self::$moderatorsByUserid,
)), self::$cacheKey, 'com_kunena');
}