Can you reset a plug-in carbon monoxide alarm with the test/silence button?

No, the test/silence button only tests or silences the carbon monoxide alarm. To reset the alarm, the unit needs fresh air and time to burn the contamination off the sensor. Push and hold the silence button for 5 seconds to silence the alarm while contamination is being burned off the sensor. You may need to do this a number of times to give the carbon monoxide alarm enough time to reset.