Server 2016 using Remove-WssComputer

Question

I have a Server 2016 essentials. Several client computers have been physical removed from the network and I am trying to find how I can remove them from the Server. The server still thinks they should be attached and the server should be doing backups. I found this procedure on the web but I have several questions about make it work. PS C:>$DeviceList = Get-WssComputer PS C:> Remove-WssComputer -Computer $DeviceList[0] -RemoveBackup
This example removes a computer identity and any backups from the network. I have run the first line in PowerShell but I am not sure what info (and syntax) I use for the second line to remove the 3 client computers that have been removed. After I run Get-WssComputer it assigns the info to $deviceList. I can run $deviceList in powershell and it shows lots of info about all the computers that have been attached to the computer. I do not know what I need to plug into the second line in order to remove the selected client. Hope this makes sense. Thank you for any help.