Help with managing Render Files

I am trying to understand how render cache files are managed.

I want to get rid of a large number of render files in the CacheClip folder.
Can I just delete them with out causing issues, (apart from having to re-render)?

If I use the automatic backup which creates a backup every 10 minutes, etc., do these backups duplicate and keep the render files from the original project?

If I create a duplicate Timeline within a project (when creating different versions), do the render files get replicated or does the new Timeline use the same render files as the original?

If I delete the unused render files in a project with multiple Timelines, does this only affect the currently worked on timeline, or all timelines?

Thanks