Mario Peshev

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

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.

pixelgrade

vlad.olaru

George Olaru

Andrei Lupu

Razvan Onofrei

cristianfrumusanu

With <a href="https://github.com/pixelgrade/pixtypes" rel="nofollow ugc">PixTypes</a> you can allow your theme to define what custom post types or meta-boxes should be active when your theme is up
Note: This plugin is addressed to developers, it doesn’t do nothing if it isn’t <a href="https://github.com/pixelgrade/pixtypes#pixytpes_config" rel="nofollow ugc">properly configured</a>.

PixTypes

A WordPress plugin for managing custom post types and custom meta boxes from a theme.

DX Remove Unused Custom Fields vs PixTypes