i was at our shooting club today .i was talking about the cost of blueing at THOMPSON and how i did one for buddy and it looked nice but black. one person said, was he using brake cleaner is that why it needed blued.i then heard another one say, IT TOOK BLUEING OFF MY BARREL ON MY MUZZLELOADER. i said no, his was worn off and a bunch of punch marks. i said, my, i use that cleaner inside my barrel. 1 said, he used a scotch brite pad cut to fit in barrel to clean and soaked it in brake cleaner. he said it took the blueing off the muzzle and all way to front sight.another said he sprayed it in the vent hole and it took blueing around hole off.ugh, i have been using this stuff too,oh my. so, i thought i might put this info on here .i think someone did say on here that he uses it at work and it does remove blueing on his ruger.i called a gunsmith and he said,dont use it. i am going to blue these friends guns for them, i just got the one 1 hour ago.like said, the blueing was all gone at muzzle and up near sight. 1 was a cabelas hawkins .50 cal , the other is a tc hawkins .54 cal.1 is 2 years old and i think the other was bought about same time as mine in 1970 area.take care.