Ans - A chimney can be cleaned with baking soda or a wire wool scrubber, which can be used to clean the inside or outside of a chimney. To clean an outdoor chimney, simply place a kettle of boiling water on the stove and pour into it ½ cup baking soda. Caution: The chemicals in some soaps and detergents damage brickwork, so it's best avoided when cleaning treated-wood surfaces such as brickwork. To clean an indoor fireplace or wood burner you'll need about six quarts of hot water mixed with one part bicarbonate of soda.