Birchwood Casey seem to have changed the compositon of their Super Blue
Liquid Gun Blue. I have recently bought the bottled version and the paste
version. Both are labelled as containing Selenium dioxide. The paste version
works really nicely on steel (in fact I think the coverage is less patchy)
but will not touch brass (as indeed the label now clearly states).

http://www.birchwoodcasey.com/sport/...=1&subcat=5#11

10 years ago (I still got the bottle to prove it) the liquid version
contained "nitric, phosphoric and selenious acid" and blackened brass really
nicely.
Is there a reason why the company changed the composition?

Furthermore, does anyone have experience with the Brass Black Metal Touch up
(15225 -BB2)?
Is it any good at turning brass black? Is it similar to Gravoxide?

Thanks,

--
Michael Koblic,
Campbell River, BC