If you have that problem with stains I sugest you use a Chrome polishing cream, like the one used for cars, some non abrasive towels, you spread a very light spill of polishing cream on the towel and gently rub the stained parts (be carefull not to spread on the headphones) and then remove gently with a "peau de chamois" as we call it in french (deer skin ?). That resulted in bringing mine (bought as second hand for a very good price
in almost good as new condition ! See the pics below ... by the way those headphones are top class sounding, very addictive, luvely, precise and punchy sound and so good looking to my taste ! Love them !
This is how they looked originally when I bought them !