Baking soda is extremely alkaline, which can be hard on lips and skin. And it requires lots and lots of rinsing with water afterwards.
For those who want to try some sort of mechanical exfoliation (which is what this is), a homemade Sugar scrub might be a better choice. There are lots of recipes online [google Sugar scrub lips recipe]. Basically, you just need something slightly gritty to rub on the lips to remove dead skin.
There is nothing magical about the use of baking soda in the recipe that is linked, it is just a handy gritty substance that most people have in their homes. Sugar is also widely available, and milder, and not alkaline, so you won't have to rinse your lips for so long.
(Or you could just use a washcloth to exfoliate your lips.)