What would people do without Google? Humanity would probably have to start out all over again; wouldn't it!
This is old information, Chen. It's been around for decades. Most of the NRA competition riflemen I used to shoot with were well aware of the need to remove impregnated residual gas and firing residue two or three days after the initial cleaning. Suggest you rev up that search engine some more.
Here's one article I found. Read Ed Harris' 1994 comments on using, 'Ed's Red' cleaning solution.
A Clean Barrel. (Toward the bottom of the page)
Why have I continued to clean gun barrels like this for all these years? I'm careful to clean any gun barrel twice on any gun that I intend to store in the safe for an indeterminate period-of-time. There ARE elements in gunpowder that, over time, can cause rust or pitting to occur underneath an oil topcoat. I've got 40 + year old guns in my safe with bores that have been well used and, still, look brand new!