Immediately cover the drain opening with a stopper or a wet rag. This traps the fizzy reaction inside the pipe, forcing the pressure to push down into the clog rather than fizzing up and out of the sink. Let it sit for 5 to 10 minutes . For a really stubborn clog, let it work for 30 minutes or even overnight.
Boil a full kettle of water. Carefully pour it directly down the drain. This softens the grease, soap scum, and debris that is causing the clog. Wait 1-2 minutes for the pipe to cool down slightly (so you don’t melt PVC glue, though boiling water is generally safe for metal pipes). clear blocked drain with baking soda
Whoosh! You should immediately hear a fizzing, bubbling, or hissing sound. This is the chemical reaction creating carbon dioxide gas. This reaction is what loosens the clog. Immediately cover the drain opening with a stopper