How to make content from secret communities totally hidden ?

Summary:

Hide courses from secret communities to members

Content (please ensure you mask any confidential information):

Hi Everyone,

here's our problem:
We have made "secret" the old communities that remain in the system for reporting purposes.
However, the contents remain visible to members in the catalog and we have to delete these items and/or members one by one...Is there a way to delete them more quickly?
Many thanks

Version (include the version you are using, if applicable):

24A

Code Snippet (add any code snippets that support your topic, if applicable):