I'm refinishing rather than buying a new bathroom vanity. One problem however is that the wood surface at the bottom of the vanity, (inside the cabinet, where you would normally store chemicals, toilet paper, etc) is warped and badly bowed into the center. I wanted to just cut and apply another thin piece right over it, shimming it or whatever else to level it but my question is, what should I coat it with to keep any future dripping from damaging it again?