I have had luck using the following technique with
watches and other HT's...
As others have said, take the battery off of the HT,
then get a Tupperware container large enough for the
HT to sit in. Pour 1 cup of rice into the container,
place the HT on top of it, and seal the tupperware
container. Check in 24 hours - the rice should absorb
the moisture that has gotten into the radio. If that
doesn't work, then I suppose sending it back to Yaesu
would be my next step...