Hmmm...I can't help but think that that 'may' work in 'some' cases, that it just won't work in every case.

I once severely burned popcorn in a stainless steel pan. Soap, regardless of what kind it was, or how it was used, didn't begin to help it. I worked on it off and on for several days using something similar to these..... Stainless Steel Scrubber Pads.

Lots of other good, and some not so good, tips at the link below.

Here is a link that might be useful: Burned Pot threads found via a seach of this forum

I, too, had burnt popcorn on a stainless steel pot, and no amount of soaking worked. I finally used straight ammonia, and let it soak for days, then scraped the rest of the residue off with a knife. A real PITA.