Pour a generous amount of bicarbonate of soda directly down the drain. A half-cup is usually sufficient for a standard domestic sink. Use a spoon or your fingers to push as much powder as possible into the drain hole, ensuring it goes down the pipe rather than sitting in the basin.
If the sink remains blocked after 2–3 attempts, the clog may be deeper (e.g., main trap or sewer line) – then use a or call a plumber. unblock sink with bicarbonate of soda
The final result is mostly water, carbon dioxide gas, and a tiny amount of salt (sodium acetate). Pour a generous amount of bicarbonate of soda