I have a serious problem with my guitar. I took all of the strings off yesterday after breaking the LOW E string. So I look at them and the bastards are covered in what I think is rust. But, it's not rust, it's tarnish coz the strings are nickel. I chucked the strings away. I'm gonna get new. But another problem is the my guitar hardware is also made of nickel (lmao) and that is also tarnished. It's all gone a funny green colour.