Have you checked if anyone has already filed anything against this problem? https://bugs.maemo.org/
If not, might be an idea to start your own tracker entry.

As for real suggestions,

stop leaving it in damp places, i once got a similar moist phone after leaving it in the old car over the weekend.
Most recently my youngest made our electronics wet with his own little stream, watch for this with siblings/children/pets.


as for the bugs calling it home, it might be possible to use ant spray or something similar - not on the device directly, but nearby and covered over (put it in a box, put some spray in and close the lid).
Dunno if that would work or what it would do to the device though..

Thanks for givin me the biggest laugh of the night so far.