@louise0102: Are you seeing the 'Moisture detected' notification at all times, or under certain conditions e.g. when charging the device? If you head to Settings > Apps > Tap the 3 lines with the downward facing arrow, to the right of 'Your apps' > Show system apps (toggle this on) > OK > Scroll down to USBSettings > Force stop > Storage > Clear cache > Clear data, then restart your device, does this help?
