I'm refinishing my pine stairs. I started sanding with 36 grit and went up to 120. When removing the finish on the sides of the stairs, some whitish stains came into view. Since I wanted the wood color to match our natural oak flooring, I went with a waterbased clear stain + poly. No luck. The stains didn't change. I asked advice from the guy at Lowe's who told me I'd have to sand it all off and start over. I thought I'd TRY to go over the poly first since it had only been two hours since I applied it. So I went over it with an oil based stain + poly (Minwax Polyshades Natural Oak). That worked, oddly enough, on every part of the stairs EXCEPT those stupid light stains. So I sanded the stained areas to bare wood and reapplied the Minwax. Still no luck. Will I have to give up and paint?