Quote from : Spindle's End Book

The magic in that country was so thick and tenacious that it settled over the land like chalk-dust and over floors and shelves like sticky plaster-dust. (House-cleaners in that country earned unusually good wages.) If you lived in that country, you had to de-scale your kettle of its encrustation of magic at least once a week, because if you didn't, you might find yourself pouring hissing snakes or pond slime into your teapot instead of water. (It didn't have to be anything scary or unpleasant, especially in a cheerful household - magic tended to reflect the atmosphere of the place in which it found itself -- but if you want a cup of tea, a cup of lavender-and-gold pansies or ivory thimbles is unsatisfactory.)