You go to your Windows PC, log into your Shield via the Local Area Network with Windows Explorer, go to the area within the drive that holds your database files to where your “Optimized File” is and you will see the “Plex Versions” folder there next to the file.
Looks like Plex creates a standard folder to where your file is. However, you can’t delete it within Plex, you have to delete on the PC/OS level.
This is actually super easy. Just needed to do it one time.