My personal belief on this subject is, you don't know if it is clean unless you can see it. I shoot competetive benchrest. I know, I know, things are different. But nobody, and I mean NOBODY cleans more than benchrest guys. Patch color does not tell you anything except when the chemical stops working. IMO when you get white patches it just means you've wiped all the chemical out. I have never got a factory barrel to the point where I thought it was clean by looking at patches. I have never got a white patch out of a factory barrel. You can't feel a clean barrel. You can feel a smooth barrel, but it can still be dirty. It is layers of carbon, on a layer of copper, on a layer of carbon, etc. You have to look in there. Get a GOOD bore scope and SEE what you're looking at. Most factory barrels are rough and will foul like crazy. A lot of custom barrels are rough and will foul too. I have had barrels from some of the best barrel makers feel rough but shoot teen aggs. (if you don't know what that is look it up.) I have had factory barrels that felt like the perverbial babys bottom shoot like crap! My point is, colors and feel means nothing! Look in there.
Edit; My experience is with CM factory barrels.I dont have any SS factory barrels. All my competetion barrels are SS Kreiger, Bartlein, Shilen, etc. If you are afraid of bad chemical reactions put a small spot on the outside of the barrel and see what happens.