I just bought a house and plan on refinishing the hardwood floors before moving in. There is some gapping and I understand the expnsion and contraction of wood, but the gapping isn't the whole floor, just select locations where it might have had a spill. Is this normal or an irrepairable stain on the floor? And if I do refinish, what is the best method to clean up all the dust from sanding, I've been told you must get it all up or it will ruin the finishing process. And also what is the best finish for the floors and how many coats is best. A long question I know but answers would really be helpful.