Mix the 1/2 cup of baking soda and 1/2 cup of salt in a bowl. Pour the dry mixture directly down the clogged drain. Try to get it as far down the pipe as possible. If you have a double sink, cover the other drain with a wet cloth to force the mixture down the clogged side.
Cover the drain opening tightly with a drain stopper or a small plate. This traps the expanding gas inside the pipe, forcing the fizzing action to push down into the clog rather than escaping up into your sink. Let it sit for at least 30 minutes. For tough clogs, leave it overnight (6-8 hours).
Disclaimer: Always test on a small area if you have antique or unusual pipes. If the clog persists after three attempts, consult a professional plumber to avoid worsening the problem.
