how to remove outgoing Received header?

[Dan Jacobson]

To make mail queued to be sent out over my modem a little smaller,
I want to eliminate this header:

136P Received: from jidanni by jidanni1 with local (Exim 4.34)
        id 1CEwoj-00046O-Ut
        for xvvvvo@bigfoot.com; Wed, 06 Oct 2004 05:25:53 +0800

I tried using headers_remove=received
in real_local, smarthost, and remote_smtp_smarthost
but none affected it.