Board Thread:Support Requests - Getting Technical/@comment-13172292-20140118181353/@comment-4018164-20140118183837

You can use a bot to do that. AutoWikiBrowser (AWB) is a very easy way to do that. It has both a way for listing all pages from a source (on this case, all category members), and an option to remove a certain category before saving the edit.

Pywikipediabot is another way to run a bot, though it requires more steps for installation, and for tasks like removing/replacing categories, AWB is much simpler to work with.

Also, it's possible to use JavaScript to remove a certain categor, because there are ways to:
 * Get all category members.
 * Get the content of a page (which can then be modified, e.g. =, removing a category link).
 * Save an edit.