How do you maintain slate floors
1 Clean a heavily soiled floor with mild detergent or slate cleaner. 2  Mix 1/8 cup (25 ml) of mild detergent in 1 gallon (3.78 liters) of water, or follow the directions on the slate cleaner container.3  Plunge the mop into the bucket and wring the mop thoroughly to remove excess water. Mix 1/8 cup (25 ml) of mild detergent in 1 gallon (3.78 liters) of water, or follow the directions on the slate cleaner container. 2  Plunge the mop into the bucket and wring the mop thoroughly to remove excess water. 3  Mop the floor, making sure to clean all areas, including along the baseboard.