Madame Glossy's Silver Polish was a magical cleaning solution, produced by Madame Glossy's Finest Cleaning Products Ltd.. It was available in three different container sizes. It is likely that as a Squib, Hogwarts Caretaker Argus Filch relied on the product quite heavily, since a number of cans of it were kept stored in a broom closet in the school. Rita Skeeter rested her parchment on one of these cans before she interviewed Harry Potter in the broom closet in 1994.