+1 for rinsing for a minute under warm water, which worked for me.
Context: after several days of swimming in salt and fresh water over the course of a week, after the last dip, the power button seemed to be stuck, going into Emergency SOS mode over and over again. After a reboot, the button was still stuck, so it could not boot: it would show the Apple logo for a few seconds then reboot again. Washing under warm water and clicking the button repeatedly fixed it.