While you can set the DHCP server to automatically prune devices that has not been seen on your network in a month or more, you may want to immediately remove a device.
Remove a device from the network
Go to Menu -> Devices
Locate the device you want to remove
Click on the device you want to remove
Click on the Delete button
Check Yes, I'm sure in the new prompt that pops up
Click Remove device
Your device is now removed from Vilfo.
Note! While the DHCP lease and any device-related settings are removed from Vilfo, it does not prevent the device from connecting to the network again in the future.