Baking soda is good for loosening soap buildup and many forms of grease and oil. Warm water and baking soda works especially well for cleaning hair brushes and combs. Alkalies generally have it in for soaps. And are far better than most "safe to use" acids at removing it.
The only risk in using it in a drain is if there's a huge soap scum or crud buildup on the walls of a pipe or sink trap. Sometimes baking soda will loosen it enough that it all comes off the pipe in one big clump and clogs the up works. Enough hot water and additional baking soda will loosen it eventually. But that can take a few days. And if there's a big wad of hair (freed from the soap scum) making up part of the blockage, all the baking soda in the world won't budge it.
I skip the vinegar and just use a half cup of baking soda and a quart or so of very hot water in my drains from time to time. Dump it in, let it sit for about ten minutes, and then flush it with clean water from the hot water tap for about a minute or two. It seems to help. But it's more a preventative maintenance thing than a real drain cleaner AFAIC.
YMMV.
Yep, what you said. Besides, the baking soda only neutralizes the vinegar, which is why you get all the fizzing...

















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