Her gran had sworn by it. “Caustic muck rots the pipes, love,” she used to say. “Bicarb’s kind. And stubborn.”
She’d read about it once. The alkaline bicarb and the acid vinegar reacting to make carbon dioxide—a gas that pushes and scours, loosening the gunk that hard chemicals only burn into cement. bicarbonate of soda unblock sink
“Gran,” she said to the empty kitchen, “you were right.” Her gran had sworn by it