For people who have some posts that allow comments and some that do not, here’s how to change “Comments Off”:
Line 720 of wp-includes/comment-template.php has the words ‘Comments Off’ as the value of the variable $none (in the comments_popup_link function)
wordpress codex: FAQ working with wordpress
To completely remove “comments off”, open wp-icludes/comment-template.php in a text editor (notepad).
look for:
function comments_popup_link( $zero = 'No Comments', $one = '1 Comment', $more = '% Comments', $css_class = '', $none = 'Comments Off' )
Change it to:
//change $none = 'Comments Off' to $none = ''
function comments_popup_link( $zero = 'No Comments', $one = '1 Comment', $more = '% Comments', $css_class = '', $none = '' )
This will make it so that nothing at all appears on posts that have comments disabled. For posts that have comments enabled, the usual message can still appear.