WSUS Offline - Does not clean up the USB/client directories

When I restarted using WSUS offline about two months ago - I intitially built my USB directory to contain updates for both Windows 7 AND Windows 10 and let WSUS do it's thing at the time.
But since then - I have dumped WIndows 10 completely and then removed the Windows 10 updates checkbox within the WSUS interfac - thinking it would ditch the Windows 10 directory and all of it's files upon the next update cycle.
But a quick check of my USB directory shows that a bunch of old WIn 10 updates are still sitting there and are coming along for the ride every time I deploy an update either server share or by copying to USB.
Why does WSUS not clean up specific update "families" if I explicitly tell the UI not "not get them" anymore?
Sonic.
But since then - I have dumped WIndows 10 completely and then removed the Windows 10 updates checkbox within the WSUS interfac - thinking it would ditch the Windows 10 directory and all of it's files upon the next update cycle.
But a quick check of my USB directory shows that a bunch of old WIn 10 updates are still sitting there and are coming along for the ride every time I deploy an update either server share or by copying to USB.
Why does WSUS not clean up specific update "families" if I explicitly tell the UI not "not get them" anymore?
Sonic.