I'm not sure what it is with this stuff but I love it. I'm pretty uptight about gun maintainance as I like to protect my investment. There has been a few used guns that I've bought and although they look clean I'll run the foam in the barrell and patch it out the next day.
I've always got a bluish residue on my patch after using that foam on a 'clean gun' that someone else cleaned. Great stuff, and usually I'm the first skeptic one about new products.