if /^\s*Received:.*Authenticated sender.*\(Postcow\)/
/^\s*Received:.*Authenticated sender:(.+)/
  REPLACE Received: from localhost (localhost [127.0.0.1]) (Authenticated sender:$1
endif

/^\s*User-Agent/        IGNORE
/^\s*X-Enigmail/        IGNORE
/^\s*X-Mailer/          IGNORE
/^\s*X-Originating-IP/  IGNORE
/^\s*X-Forward/         IGNORE