Click Formatting: use Plain text in top box, and Convert to plain text in bottom one.
I choose use HTML to compose on top and "Ask me what to do if the message has HTML, otherwise send plain text." I can choose by addressee whether to send text or HTML that way. It allows me to use formatting for emphasis and embed HTML pages to some and plain text to others. It only asks if I include HTML in the body, so it is not a routine bother. You can make mistakes and send HTML to the wrong addressees, so the list above is preferred for an e-mail list.
Materials found at U. S. Scouting Service Project, Inc. Websites may
be reproduced and used locally by Scouting volunteers for training purposes
consistent with the programs of the Boy Scouts of America (BSA) [Links
to BSA Sites], the World Organization of the Scout Movement (WOSM) or other
Scouting and Guiding Organizations. No material found here may be used or
reproduced for electronic redistribution or for commercial or other non-Scouting
purposes without the express permission of the U. S. Scouting Service Project,
Inc. (USSSP) or other copyright holders. USSSP is not affiliated with BSA or
WOSM and does not speak on behalf of BSA or WOSM. The NetCommish website
is for Scout Leaders, Scouters, Scoutmasters and Commissioners. Opinions expressed on these
web pages are those of the web authors.