I purchased a Rudall Carte Starline trumpet recently because it was advertised as having a copper bell. I've been curious about the sound of a copper bell horn. I know I could have made better choices to find this out. Nevertheless, the photos on ebay did look like copper, but when I polished the horn with brasso the enamal came off in large areas revealing a silver/nickle metal. I never mind that because I usually like my horns raw, but I didn't expect the copper bell to discolor in that way. My main question is, if this bell was true copper would it show any silver/nickle splotches?