When accessing the UltraHub router, I see that under Overview it lists the devices that are connected to my LAN through the router.

It also lists devices that have been connected in the past, and these are greyed out..... some have been visitors that are highly unlikely to use my network again, others have just been test set ups.

Question is, how can I remove these dead bodies? 

Hitting Factory Reset could be a bit drastic for something simple