I recently refinished the hardwood (oak) floors in my newly purchased home. I did the basics; drum sand, clean, stain and seal. I used boiled linseed oil for the stain, and a water based poly-acrylic for the seal. The floors looked amazing when the job was complete, however they are developing black stains throughout floor. I think it's because of the polyacrylic sealer, but would like others advice on how to remedy this.. .