It's not necessary to leave a copy back in Storage, you can just move them instead of copying them. Then when (if) you need to change back and move them back again, you won't have trouble because of duplicate files.
If you are afraid of losing any of them or whatever, the solution would be to make a proper backup of the whole volume before making potentially risky changes, not to leave identical copies of files in both places.
Best regards,
Niels