Here is a good article on passivation I think every brewer should read to put to bed some of the bad information still circulating.
"A common misconception among home brewers is that passivation can be done with any acid. Many brewers have an oxalic acid, phosphoric acid, and/or any abrasive based cleaner handy and think that it can be also used to passivate their stainless steel. These cleaners can help remove residue, remove rust, or bring the stainless steel surface down to bare metal, but they do not selectively remove iron. The stainless steel surface will form the oxide layer (as it normally does), but without a correct acid treatment the chromium only covers about 18% of the surface. In other words, there's no passivation benefit from these acids."
https://brewingforward.com/wiki/Passivation
Very good information, thank you.
Bar Keepers Friend isn't one product, there are many.
https://www.barkeepersfriend.com/I went to Bar Keepers Friend website to check ingredients in their products.
There are two products, based on label, a home brewer would probably
select. The "powdered cleanser" and "soft cleanser" versions, both have oxalic acid.
But only the "soft cleanser" version includes citric acid, and has more citric acid than oxalic acid.
After I use the "soft cleanser" version on SS pots, the pots will have a very slight blue sheen.
I'm solely focused on the home brewer scale. It's obviously impractical for commercial
brewers to use a scrubby on many large tanks.
If my Father was still around I would pick his brain, he was a Metallurgist.
Innocent oversight on the authors part under Myth Busting. Bar Keepers Friend is a brand name, not a specific product.
Their "powdered cleanser" product was commonly used, as was Comet. Since the
"soft cleanser" version includes citric acid, and not solely oxalic acid, it nullifies
the belief "Bar Keepers Friend" won't work.