Can someone help me out? For some reason, there are rogue values appearing in my list of custom field keys. See the screenshot:
The only one that I've created was thumbnail and that should be the only one to show. The rest are URLs to videos. I thought they may have been caused by a video plugin, but I've since deleted that plugin and all known instances of the URLs on the site.
How do I remove these unneeded keys from the list?