Mario Peshev

<p>Delete all Custom Field entries assigned to posts that do not exist in the posts table.</p>
<p>Navigate to Settings -> Remove Unused CFs and delete all postmeta for non-existing posts.</p>


DX Remove Unused Custom Fields

Does exactly what it says.
Installed, navigate to the settings page, click "Delete" and Done! Cannot be easier than that.
Thank you!



Simply Awesome!

Delete the Custom Fields from your postmeta table where assigned posts no longer exist.

dauidus

<p>Add Post Type Instructions allows admins to easily set instructional context for metaboxes and more on pages, posts or custom post types.  Currently it supports adding instructional context in the following areas on the add/edit screen:</p>
<ul>
<li>above the title field</li>
<li>above the WYSIWYG editor</li>
<li>default content within the WYSIWYG editor</li>
</ul>
<p>and within the following metaboxes:</p>
<ul>
<li>publish</li>
<li>author</li>
<li>featured image</li>
<li>excerpt</li>
<li>trackbacks</li>
<li>custom fields</li>
<li>page attributes</li>
<li>categories</li>
<li>tags</li>
<li>post format</li>
<li>discussion</li>
<li>comments</li>
<li>revisions</li>
<li>slug</li>
</ul>
<p>APTI uses OOP standards to add options only for those metaboxes which are supported for each post type and to execute code only on those pages where it is needed.  It works especially well for sites with many custom post types that require content to be entered in a specific way (ie. when a post type requires a specific page template or when the absence of a featured image will break the intended look of a post).  Think of any theme or plugin that supports an image slider powered by a required featured image, and you can surely see where APTI can come in handy.</p>
<p>To be clear, APTI does absolutely nothing to the front-end of your site.  It simply adds instructional context to the add/edit page/post admin screen so your clients and site editors might better understand how content is to be added.</p>
<p>APTI works with multisite networks and allows users to define settings on a per-site basis.</p>
<h4>Coming soon</h4>
<ul>
<li>Translations – to submit a translation, please contact the author</li>
</ul>
<p>APTI will work with drag-n-drop builders such as Visual Composer, but the author cannot recommend its use with them.  This will be addressed in a future release.</p>
<h4>Suggestions are welcome</h4>
<ul>
<li>email the author at dave@dauid.us</li>
</ul>
<h4>Follow Development on Github</h4>
<ul>
<li>https://github.com/dauidus/add-post-type-instructions</li>
</ul>


Add Post Type Instructions

Absolutely fantastic, every design decision is spot on, looks like native WordPress.
Options to configure as you need per-post-type and being able to pre-populate the wysiwyg is a great optional bonus.
I have a site with multiple post types, many authors and some very specific posting requirements. Following instructions written elsewhere hasn't proven that effective but I'm confident having instructions directly next to the fields is going to make everything go so much more smoothly.



Brilliant

Allows admins to easily set instructional context for metaboxes and more on pages, posts or custom post types.

DX Remove Unused Custom Fields vs Add Post Type Instructions