Although both the Google and Nest Min speakers are very reliable there will be times when you will want to rest the speakers back to factory default. An example being when you get a new router or modem. I have found it better to reset than try to change them over. Another example would be if you wanted to give one of your Nest Mini speakers to someone else you should reset it first.
The older Google Mini have a different colour base (mine are orange) and do not have a keyhole for hanging them on a wall. For these you will find a small circle on the base next to where the power cord plugs in. Hold for around 20 seconds and the mini will give you a warning that you are about to rest – continue to hold until the reset occurs.
The newer Nest mini speakers don’t have a button underneath but do have a keyhole. To reset turn off the microphone switch on the side, then press down in the centre of the speaker on the top for around twenty seconds where the four lights come on. You will get a warning about reset then continue holding until complete.
Now you can go back into your Home app and add it back in.