Stinky bottles/sippy cup fix!

I had some bottles that smelled like old formula even after washing in dawn and boiling. They are Dr. Browns so I couldn’t toss them and I was desperate for a easy fix. My mom told me to soak them in baking soda water. You’re supposed to add like a table spoon per 1 cup of water but I just filled my sink with scalding hot water and poured about 2/3 of a small box of baking soda in and let them sit until the water was cold. No stink! No nothing! Washed with hot water and dawn and let air dry completely. You would never even know they were used!