A slow-draining sink is a universal frustration. Before you reach for a toxic, gel-based chemical cleaner or call an expensive plumber, there is a powerful, safe, and inexpensive solution already in your cupboard: bicarbonate of soda (baking soda).
Quickly cover the drain opening with a plug or a damp cloth. This traps the carbon dioxide gas inside the pipe, forcing it to push against the blockage rather than escaping upwards. Leave it for 15–30 minutes . sink unblocker bicarbonate soda
Pour ½ cup of dry bicarbonate of soda directly into the drain. Try to get it past the drain strainer and into the pipe. A slow-draining sink is a universal frustration