We have refinished our basement with tongue and groove knotty pine. We wanted it protected with a clear coat. We used an oil based varnish on one wall and hate it. It changed the color to golden and has shiny spots. Our neighbor told us we should have used water based polyurethane. So we sanded the wall for days. It looks the same as the rest of the room but we want to be sure we can use a water-based poly over it now. Can you tell us if it would be safe to use.