Wood floors are delicate surfaces that should be handled with more care than many other types of flooring. Using too much water can cause the wood to swell and buckle, while using the wrong cleaning products can cause damage to the wood surface. Black streaks can sometimes form between the wood joints, because residue sets in between the cracks of the wood panels. The streaks can be fairly easy to remove, requiring the use of a few simple household products.
Mix a cleaning solution by combining 1 cup of white vinegar and 1 gallon of warm water. The warm water will assist in breaking up the residue, while the white vinegar will clean and cut through the black residue.
Dip a cleaning cloth in the solution, and wring out the excess water. Wipe the cloth across the floor, working in 2-foot by 2-foot sections at a time. Apply extra pressure to the black streaks between the joints. Cleaning by hand will allow you to reach between the cracks more easily.
Dip an old toothbrush in the cleaning solution, then scrub between the wood joints. Repeat until all of the black residue has been removed. The process may take two to three repetitions until all residue has been removed.
Wipe over the area with the damp cleaning cloth once more to remove loosened residue.
Dry the floor by wiping the area with a clean, dry cloth. This will collect excess moisture, and prevent the wood from swelling.