You can reset a Google Chromecast to its factory settings if you're having issues with it or if you get a new wireless router ...
To set up a new Google Chromecast, you'll need a compatible TV and a smartphone with the Google Home app installed.
The other way to unregister Chromecast or another device is through the Google Home app. Follow these steps to unlink the device from your account: Open the Google Home app to the Devices tab. Select ...