I've seen posts about deleting folders (which deletes completed projects in the folder); so, I don't want to delete a folder I'm not using anymore. My guess was that you could change the folder to a state of 'Complete,' but alas the only choices for a folder are: Active or Dropped. Dropped doesn't sound right, so I'm baffled as to how to clean up my lists of folders that contain only completed items that I won't be using anymore. Any advise?

[Toadling]

I think the states for a folder should be "Active" and "Inactive", or "Enabled" and "Disabled". But I don't think it's fitting for a folder to be "Completed", that state should be reserved for projects and actions.

But regardless of what a folder's states are called, I think the functionality you're looking for is already there. If you're done with a folder and want to hide it from view, just mark it as "Dropped". That's what I do. I also use dropped folders for my project templates.