TheBat
Instructions for sending plain text mail and/or turning off HTML in TheBat
Even though TheBat always writes in plain text it is multi-lingual and users may experience problems because of accented characters and foreign character sets.
If you are using TheBat in a non-Latin country you need to make sure that you are using the Latin character set. To turn this on you need to specify %CHARSET="ISO-8859-1" in your address book template for New and Reply messages to the list.