That was very helpful. It is good to be able to remove "old"/"legacy" devices from the router. What is the point of having a legacy device name remain on the router if the device is never going to be connected again?
I was doing some trouble-shooting on my router and your instructions were 100% correct. Thank you.
The problem with inactive devices is: If they were connected to the primary network, and are now inactive, but you want to connect to the guest network the router does not allow. Once on the primary network, devices cannot join the guest network. this is a problem for someone attempting to improve security by moving IoT devices to the guest network. Factory reset of the router is really not an option. Good suggestion about setting static IP, and deleting, but on the G3100, delete does nothing:(