I have a very old house. The house has hardwood floors. The outside 18" perimeter of the floor was stained but the inside was not. I sanded all of the old stain off and sanded the middle of the floor as well. The wood that once was stained looked very fresh while even over-sanding the did not reveal such a fresh looking wood. I stained the floor, putting one extra coat on the outside perimeter to accommodate for the color difference. All looked well. I polyurethaned the entire floor. The outside perimeter dried just fine but the inside is extremely tacky after 24 hours. What can I do?