With all the new products out there, it is hard to find a finish that is best for new wood windows. The windows are nice, fiberglass outside and clear pine inside. What should I use to stain and seal the windows interior? Taking into account window condensation and UV protection. I have used stain and urethane in the past, and after a few years have had dark streaks near where the wood meets the glass, from possible condensation soaking into the wood, I have also had some flaking of the urethane due to UV most likely. I just would like to know the best practice these days…..