According to Xin Kai's inquiry experience. Com, the discoloration of yak bone bracelets is caused by the reaction of human oil and sweat. Black yak bone bracelets and brown yak bone bracelets are always black and brown, and only white yak bone bracelets will turn pale yellow and white in the later stage. Therefore, as we all know, vinegar does not contain oil, so it will not react, so it will not change color.