php-developer

This plug-in remove all comments from your current word press site. When Plug-in is active its remove all comments for all user. You can also remove comments from specific post type.
You have a option to removed comments only from posts or pages.
You can also remove from custom post type. For that you have to add code in your current theme`s function.php file.
Note: When you select “Yes” to “Do you want to remove all comments?” Its override all other option settings.

Remove All Comments

This plug-in will removed/Delete all comments from posts and pages.

javatopsystems

JavaTop No Comments completely disables the WordPress comment system across your entire site. Activate and comments are gone — no configuration required.
What it does:
<ul>
<li>Closes comment and ping threads on all posts and pages</li>
<li>Removes comment support from all post types</li>
<li>Removes the Comments menu from the admin sidebar</li>
<li>Removes the Comments node from the admin toolbar</li>
<li>Removes the Recent Comments dashboard widget</li>
<li>Removes the Comments column from post and page list tables</li>
<li>Redirects any direct access to the comments admin page</li>
</ul>
What it does not do:
<ul>
<li>Delete existing comments — if you deactivate the plugin, existing comments reappear</li>
<li>Affect comment data in the database</li>
</ul>

JavaTop No Comments

Disables comments site-wide with a single click. No configuration required.

Remove All Comments vs JavaTop No Comments