Two weeks later, he was down in the basement again. This time, it wasn't the shower that was the problem. It was a dark, wet stain spreading across the drop ceiling tiles directly beneath the bathroom.

The acid reacts with these metals.

He knelt, placed a rubber mat over the sink’s overflow hole, and donned a face shield that had more scratches than glass. His gloves were elbow-length, black, and slick.

Because sulfuric acid is heavier than water, it sinks through standing water to reach the source of the blockage directly. Benefits and Effectiveness