¾ Cup Baking Soda
½ Cup White Vinegar
Put ¾ Cup Baking Soda down the drain. Then pour ½ Cup White Vinegar down. Either plug the drain or not. There will be a bubbled reaction. Up to 30 minutes later add hot water to the drain to remove clog. Repeat when needed.
I tried this method a few months ago and it had an amazing result. So this time the clog was real bad. So today we added baking soda and vinegar and thought for sure we would have to call a plumber, the clog was that bad. Then out of the blue the water gushed down the drain and you could hear the clearing of the drain as we ran hot water down it. We used more baking soda and white vinegar than was recommended by the recipe I found but the result is so fantastic. Baking soda and white vinegar is my go to with a clog from now on.
I recommend this method on even the worst clogs. Of course should it not work then call a plumber but give this method plenty of time to work before calling.