12.5 Comment Lines
Lines starting with zero or more whitespace characters followed by one
'#' and a whitespace are treated as comments and, as such, are not
exported.
Likewise, regions surrounded by '#+BEGIN_COMMENT' ... '#+END_COMMENT'
are not exported.
Finally, a 'COMMENT' keyword at the beginning of an entry, but after
any other keyword or priority cookie, comments out the entire subtree.
The command below helps changing the comment status of a headline.
C-c ; (org-toggle-comment)
Toggle the 'COMMENT' keyword at the beginning of an entry.