A strong enough acid (using too much) will do that to solid brass too. That's dezincification where the acid eats the zinc out of the brass. Pink brass is not good as it's weakened. And if you load up that brass and let it sit for a few years it'll likely split or you get a head separation or something bad along those lines. It makes me cringe to see some of these guys doing youtube videos and dump a bunch a Dawn (which contains a constituent of ammonia) and Lemishine (citric acid) in their chlorinated and fluoridated water and use it hot to tumble and rinse. Heat puts the process on steroids. Rule of thumb is a tiny amount of each as the water and pins together do the vast bulk of the work.
