rehydrate my project

[Diehlicious!]

I have a two year old project that still hasn't had the top and bottom put on. it's been in a very dry place in nevada, now in Missouri. It needs to get rehydrated a bit. Any suggestions on how to get the inside and outside of the walls a bit more hydrated. They're probably around 10-15% so a hair dry, winter in Mizzou is almost as dry as Nevada in the winter.
Thanks everyone!