Special wet wipes should be used to clean the smartphone screen, and a microfiber cloth for the final wipe, because using such wipes will avoid damage to the screen.
It is advised to use a plastic ounce in order to protect the screen from scratches, and not to use alcohol to clean, because it causes damage to the device from the inside, and it is important to clean the connectors regularly and not to use metal objects because they may cause mechanical damage.
You can clean the speakers by using a toothbrush, or wet wipes with alcohol sanitizer while avoiding that the liquid does not get inside but only to remove germs.