Cleaning up TheDude files after migration

On one of our Dude Servers (which this is a new server so I could net-install this if it’s absolutely needed, but I cannot remove the files from the /dude/files/* directory from the router either through FTP or Winbox. I am being told that these are locked in read-only.

How can I delete /dude/ and all of it’s contents out of the file system on this router without a netinstall or is that not possible?

Paul