Ok Henry you remember my wood floor. I really respect your opinion, so let me bounce this one off you. I agree that silicon would work, and the finish would not stick to it. How about an acrylic caulk? Or a polyurethane caulk? I am not sure if polyurethane comes in clear or any wood colors but what do you think? even if the finish came off of the poly caulk that would probably be ok. Remeber it is a rustic look I am after.