But Carl added one more thing: . He handed her a small metal mesh strainer (99 cents) and said, “Pop that over the drain. Empty it every shower. You’ll never snake it again.”

“You don’t need acid,” he said. “You need mechanical action and time .”

Then he poured ½ cup baking soda down the drain, followed by 1 cup white vinegar. It fizzed violently for two minutes. “That breaks down the grease and soap scum holding the hair together.” After the fizzing stopped, he poured the full kettle of boiling water. Whoosh—the water vanished.

Sarah tested the shower. Perfect.