Mozilla Mailnews FAQ

How do I remove structured words symbols?

If you want Mozilla to hide the signature separators and the symbols around *bold* /italic/ _underlined_ words in plain text messages, add the following to your userContent.css:

.moz-txt-tag { display: none; }

If you only want to alter some types use:

*bold*:
.moz-txt-star > .moz-txt-tag { display: none; }

/italic/:
.moz-txt-slash > .moz-txt-tag { display: none; }

_underline_:
.moz-txt-underscore > .moz-txt-tag { display: none; }

|code|:
.moz-txt-verticalline > .moz-txt-tag { display: none; }

-- (Signature):
.moz-txt-sig > .moz-txt-tag { display: none; }