public function clean($string)
    {
        if (!empty($string)) {
            $string = preg_replace('#<script(.*?)>(.*?)</script>#is', '', $string);
            $string = htmlspecialchars(strip_tags($string, $this->_allowableTags));
            $string = str_replace('href=', 'rel="nofollow" href=', $string);

            return $string;
        }
        return false;
    }