Let me try and explain again
I imported books/docs from a folder and sub-folders not realising that it also included some pdf and lit files. I'm not interested in the lit files, but some of the pdf files relate to research and published scientific papers which I have no wish to include in Calibre in case I inadvertantly change or delete them. I have backups of these files and I know I can filter them so they don't show, but all I wanted to do is remove them from the calibre library, without permanently deleting them from the hard drive.
I want to keep them in the original folder/sub folders for archival reasons, hence the reason for copying them back after deleting from Calibre.
What I thought would be a simple question, turns out to be more difficult than I first thought
Thanks for all the help
John