The more time that elapses, the more difficult it will be to remove stains. Step 2 Tackle white marks To remove white marks on wood, like the rings left by a hot mug or a wet glass, make a paste of equal parts baking soda and white toothpaste (not gel).he more time that elapses, the more difficult it will be to remove stains. Step 2 Tackle white marks To remove white marks on wood, like the rings left by a hot mug or a wet glass, make a paste of equal parts baking soda and white toothpaste (not gel).