Carry a small, flask-like vessel of cold salty water, and when the
caller has finished the call, ask to borrow their phone...and place it
in said water.

No more calls on that journey


I had a Nokia 3310 which fell in the toilet (still not quite sure how).
For reasons of hygiene, I washed it very thoroughly, and then took it
apart as much as I could, thinking that the components are mostly
sealed in plastic and/or non-corrosive.

I then laid all the little, thoroughly-washed, bits out to dry for two
days.

Then I put it back together again, and it didn't work.

So the water may not need to be salty.