[Unclenick]

I don't know what the chemistry is. Peroxide accelerates about any etching process. We used to use it with sulfuric acid to better etch circuit boards. The No-lead may have some, as the kit I got came in two bottles I had to mix. I spoke to them and they said it's because the pre-mixed compound can lose potency during shipping. They felt it should be stable after it gets to your home, but I've kept the two separate and mix only as-need.

A lot of folks use vinegar and peroxide to attack lead in a bore and turn it into lead acetate, which is water-soluble, but that can etch steel, too, and can destroy bluing. The No-lead is safe and doesn't seem to bother anything but the lead. I'd have to look up black lead compounds to try to guess what they're using.