Hello all! I have been reading this website for a long time. I have never posted though. This is my first! I can almost always find the answer I need, but I didn't tonight. I just bought a new house and started refinishing the red oak hardwood flooring today. I have done this several times before, and I am pretty good with a drum sander and edger. I started in the master bed room this afternoon and everything went great. The floor sands easily and looks wonderful after. That bedroom floor did look a little different than the rest of the flooring in the house though, but I didn't think much of it. Well, when I moved to the 2nd bedroom, the sandpaper on the drum completely clogged up with what I think is shellac in just a few feet of sanding. The reason I think it is shellac is because after this happened I poured a little bit of denatured alcohol on the floor and after about 30 seconds it dissolves the finish. Obviously, I figured I have to get all the shellac off, since it seems it won't sand off at all, it just melts on the sandpaper. I tried to use denatured alcohol and rags, but it doesn't work very well and is very time consuming. What should I do? I am using 60 grit sandpaper as a first cut since the floors are very even and (I thought) the finish was very thin. Would a lower grit be less likely to melt the shellac and clog the paper? Will I have to use a chemical stripper?