Re: copper fouling!!!
I agree with the above re. copper removal, you can patch forever and still get traces. I would like to comment on your choice of cleaners. You are using a heavy ammonia cleaner; ammonia can be a tad excessive for normal cleaning and can be damaging to aluminum (with prolonged exposure).
Perhaps you may want to try a less agressive product now you are aware that all the copper will never be removed. Save the stronger stuff for extreme cases. Some people have good luck with foams, others like liquid; I prefer Butch's bore shine as it can be left for an overnight soak. I use Sweets for heavy cleaning and am careful about the time it stays in the bore, that stuff is powerful, it will about take Lincoln off a penny.
If you have a chromed bore it should be a rather easy cleaning surface.