I'm fairly certain that Boris does not have a chain of office, and he would certainly not be polishing it anyway.
There IS a chain of office, the Lord Mayor of London wears the celebrated collar of SS. This consists of twenty-six S-shaped links, with alternating knots and roses, all in gold and enamel, joined by a Tudor portcullis from which hangs the Mayoral jewel. The collar was presented by Sir John Allen who was Lord Mayor in 1535 and was enlarged in 1567. The Mayoral Jewel is surrounded by twenty-four rose-cut diamonds and was made in 1802 and re-set in 1806. It consists of a cameo of the City Arms, surrounded by the City Motto in blue enamel and wreathed in roses, thistles and shamrock in brilliants and rose diamonds.
But this is for the City of London Mayor, a ceremonial post now. I've seen it up close and it is quite spectacular, but not 'my' sort of jewelery :-). It is polished professionally and the person wearing it is (hopefully) most careful not to touch it. I always wince when I see people holding up and messing about with ceremonial cups and bowls which are presented to a series of people. eg the tennis trophies and various sports trophies. Do you know how much work goes into keeping stuff like that dent free, clean and tidy?
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Mayor of London, on the other hand, is an administrative position covering the whole of the Greater London area.
