Antique Cadbury Bournville Chocolate Tin 3 British Queens (Landermere CO16)

Tin is very old - and looks it, it isn't shiny, has some scuffs and is a bit grey inside. But it looks like it is from the early 1900s, Queen Mary, and it might clean up if anyone knows how to. Charming old tin, with reference to the three queens on the bottom - Queen Mary, Queen Victoria and Queen Alexandra.