Quoted from Patofnaud:Step 1, remove everything from the cab, take it out doors, scrub it up with a good bristle brush and hit it with a high pressure air hose and see how bad it really is.
It the cab is really bad you can rebuild it, replace it with a new cab, or just clean it up and play the crap out of it until the bottom falls out.
Hmmm, I think it probably is gone. Any moisture/mold/bacteria in that wood is going to haunt you later. I'm thinking replacement is the way to go.
I would look at this as an opportunity to make a custom cabinet, because I would have a hard time doing something crazy to an original cabinet, but with used or custom made cabinet it would be like a blank canvas.