Andreas Ostheimer

Delete & Disable Comments is a powerful tool for WordPress administrators to efficiently manage their site’s comments. With this plugin, you can:
<ul>
<li>Delete all spam comments with one click</li>
<li>Delete all comments (with option to create a backup first)</li>
<li>Disable comments site-wide</li>
<li>Download a backup of your comments before deletion</li>
</ul>
The plugin is designed to be simple to use while providing robust functionality for comment management.

Delete & Disable Comments

A WordPress plugin that helps to manage comments by deleting spam comments, removing all comments with backup, or disabling comments site-wide.

Sam Margulies

Ever have one erroneously entered custom field name confuse all of your users and you just can’t figure out how to get rid of it? Delete Custom Fields will let you delete every instance of a custom field from your site. Once your remove a custom field using this plugin it will not appear in your list of custom fields when you edit a post or page.

Delete Custom Fields

Doesn't show all custom fields, though (even if you choose Show Hidden) - would be nice to have them as a list instead of a dropdown, but otherwise it does what it promises.

Works

Remove every instance of a custom field from your site.

Delete & Disable Comments vs Delete Custom Fields