This is a favorite on social media, mostly because of the satisfying fizzing reaction. However, physics tells us that the reaction creates salt and water, neither of which clears hair clogs well. It is excellent for deodorizing a smelly drain and works well as a maintenance step to keep pipes clean, but it rarely clears a full blockage once the water has stopped moving.
For minor blockages caused by soap scum or grease, boiling water is the easiest and most eco-friendly first step. how to unblock bath drain
A long, flexible metal coil that you manually crank to break through or hook onto deep blockages. This is a favorite on social media, mostly