Removing hard water buildup on windows
To remove a hard water buildup on windows, pour straight vinegar into a cloth. Rub windows with this solution, then rinse with fresh water. If this does not work, use one of the following: one quart warm water and two tablespoons household ammonia; or one quart warm water and three tablespoons denatured alcohol, or a commercial window cleaner. Dry wet surfaces with newspapers, paper towels, or a chamois. Avoid washing windows in direct sunlight because they tend to streak.
Removing water marks on furniture
Water or heat marks on furniture can be removed by rubbing with mineral oil or furniture lemon oil. Pour a few drops of the oil onto the spot and rub the area with the oil and a soft sponge. With a soft cloth remove the excess oil.