I dunno about "treating" the wood... hey! I'm a guy who doesn't worry about water spots on his drinking glasses, ya know? I've been using some wooden bowls I purchased online about eight years ago, from the
Old Dominion Soap Company (bottom of the page); I store soap and build lather in all of them, with no problems.
What I will say is that if you plan to build a lather in one, make sure it's sufficiently high -- about twice the height of the soap; if not, it gets real messy, real quickly.
Smooth shaving!