Apply a clean, dry cloth to the affected area on the carbonized strand-woven bamboo flooring. Soak up any excess moisture. Prolonged contact with water could result in a more severe stain or permanent discoloration.
Spread a mixture of equal parts mild abrasive and lubricant onto the water stain. Suggested combinations include cigarette ash and mayonnaise, or non-gel toothpaste and baking soda.
Take another clean, dry cloth and rub the abrasive/lubricant mixture in the direction of the grain. After a few rounds of rubbing, wipe the abrasive/lubricant mixture off the affected area and assess your progress. If there is no improvement, proceed to the next step.
Ventilate your work area. Dab an extra-fine (0000) steel-wool pad in a small amount of mineral spirits. Gently polish the affected area in a circular motion. After a few rounds of polishing, wait for the mineral spirits to evaporate from the affected area and assess your progress. If there is no improvement, proceed to the next step.
Use an orbital sander to lightly sand the top layer of the water stain with 150-grit sandpaper. Clean off the dust and use a natural-bristle brush to coat the affected area with the same finish as the rest of the bamboo floor. Wait for the finish to dry completely, then lightly sand the spot with 220-grit sandpaper. Clean off the dust and add another coat of finish. Repeat as necessary to ensure the water stain is removed and the affected area blends in with the rest of the bamboo floor.
Wait until the last layer of finish has dried completely before walking on the spot again.