Well, it's a very personal question... oh I see
You mean chrome and nickel bits or the Japan? I don't bother with the Japan, since the Singer oil does a great job at making it glisten. For the plated parts I use Silvo - not sure if this is world wide, but I used it when I lived in the UK and now in Australia: It's just a metal polish though, so I imagine any good metal polish will do. Makes a very big difference.