OT
I was planning to replace my 1.5 yo smartphone, because the clickyness of its volume button had disappeared. nothing helped.
then I read about this great fix:
... put a little water over the button and push it several times until the clickyness comes back, then suck the water (and probably dirt) out of the button... (did it with a vacuum cleaner). worked like a charm!
never thought a volume button clicking would feel so wholesome....
is your phone not IP68 rated?
i just wash my smartphone with soapy water in the sink and dry it with a cloth as mine get dirty all the time from my outdoor activities.