Deleted Zwave items keep popping up in Inbox as "unknown devices"

The software @Bruce_Osborne is referring to is called Z-wave PC Controller. You can manage your zwave network from there to delete bad nodes.

Be very careful though as if you make any mistakes, you may need to reset and re-add your entire network in OH again.

Here’s a mirror (free registration required). I believe the latest version is 5.38.