It is not true that chrome is maintainance free.
But it is hard to find a solution...
Until you learn that bees wax does the work. Melt bees wax and mix ten percent carosin into it and put it in a plastic cup to cool. Press out the lump and you have your "tool". Warm the chrome part to be threatened, just warm, not hot, and put some wax on it. Then rub it in thoroughly until it's not visible anymore. If it's a large part you might have to warm it several times, or it'll be weary hard and time consuming.
Bees wax is the only thing that can penetrate chrome. I usually does this during winter and if done correctly, and not to aggressive detergents are used when cleaning the bike it'll last for the season, even here in cold and rainy Sweden.
Oh, I never uses any cleaning detergents on the bike that I'm not prepared to wash my face with...