And then use (green! it's traditional) felt to line the inside of the
box. It'll help protect the tools and absorb fluids.

Snag wrote:

I'm a master cabinet maker , and my advice is to finish it inside with the
same type of finish you plan on using for the outside . The reason for that
is to control moisture absorption . With the same type of finish in and out
, the wood absorbs equally on both surfaces , and maintains balanced
internal stresses . Leave a raw piece of wood on a (very) wet surface and
you'll understand ...