Natural warmth and beauty make wood a favorite for floors. But when the topcoat finish wears through, the porous surface of the wood is open to stains-especially beneath dining room chairs, in front of a sink and in other high-traffic, high-spill areas. Oil soap and all-purpose cleanser remove some stains, especially when the spill is fresh. But it's impossible to scrub out stains that have soaked into the wood fibers. And sanding only creates a depression in the floor that's more noticeable than the stain. The only option to repair hardwood floors at this point is to cut out the stained floorboards and install new ones. We replaced a couple of boards from a standard 3/4-in.-thick x 21/4-in.-wide oak-strip floor using a drill, circular saw and sharp chisel. To determine the exact width and thickness of the pieces you'll need, lift up a heat register or threshold and measure the exposed ends of the floorboards. You'll find hardwood flooring at a local millwork shop, lumberyard or floor-covering store.