public function strip()
    {
        if (empty($this->_message))
            throw new RuntimeException("A message has not been set");

        $messageBody = $this->_message;
        if (preg_match_all($this->_regex, $messageBody, $matches)) {
            foreach ($matches[0] as $k => $header) {
                $startPos = strpos($messageBody, $header);
                $lookAhead = $k+1;
                $afterPos = array_key_exists($lookAhead, $matches[0]) ?
                    strpos($messageBody, $matches[0][$lookAhead]) : strlen($messageBody);

                $messageBody = substr($messageBody, 0, $startPos) . " " . substr($messageBody, $afterPos);
            }
        }

        return trim($messageBody);
    }