Cuisinart Copper Mixing Bowls, Set of 3

Had for a day and was cooking meat (maybe I’m not supposed to put raw meat in a copper mixing bowl?) idk but as soon as I went to wash the pot a few minutes later, it left this weird residue alongside the mixing bowl. I don’t honestly mind because no one sees the inside and I love when copper starts to patina over time so when that happens to the outside I won’t mind. They function really well and look good in my open shelving too. I’m all about it but that was a weird effect that happened to just one of the bowls so quickly.