Copy and Paste
When I forward a message, I "copy" the main body and click on "Forward". I then "paste" the copy above the "original" message and delete the original. Granted, the headers are still intact, but at least the message content has been made readable - occasionally, I even need to clean that up as some mail programs insert "=" at the end of some lines or some other such crud. When forwarding non-important stuff (e.g., jokes, cartoons, etc.), I also bcc my copy list and send to either myself or "undisclosed_recipient" and delete the rejection to "u-r". This at least keeps the "cc" list a little shorter (and protects the other receivers from any prying eyes that happen to be looking when the e-mail is opened - again the headers remain). If I had thought of it way, way back then, I would have requested an actual e-mail address of undisclosed_recipient (or some other bogus address) just for forwarding jokes, etc. and forwarded those type of e-mails to that address. Actually, I do everything mentioned in the article.
