To quickly and easily remove all unwanted comments when using Sublime text, perform a search and replace (CMD, ALT & D) and enter the following. Make sure that regex search is enabled by clicking the small icon in the bottom left that looks like an astrix.
Remove all HTML comments:
(?s)<!--.*?-->
or remove all HTML comments and trailing newline if it exists:
(?s)<!--.*?-->\n?
Search and replace with blank.
Remove all CSS comments:
(?s)\/\*.*?\*\/
Bonus: Remove blank/empty lines?
^\n