 You should replace the Sonnet microphone cover if it appears dirty or if you notice a change in sound quality. You should change the cover every three months for the best sound quality. To replace the microphone cover, remove the ear hook. Pull the microphone cover off the control unit from the front using your fingernail. Insert the pins of the new microphone cover into the recesses in the control unit. Make sure both pins are in the control unit. Carefully snap the microphone cover onto the control unit. Reattach the ear hook and use the ear hook pin to lock the ear hook in place.