Leaves and dirt may stain concrete surfaces or, after removing the winter cover, you may see a pronounced color difference. Pressure washing can remove these soils and restore original brightness to concrete and coping stones. A light acid washing on the coping stones also works very well, and algae or mildew can be lifted by scrubbing in a paste of calcium hypochlorite. Read all precautions before working with these dangerous chemicals in this manner.
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