Chicago pottery merchant has been using mark since 1997.
“Chicago pottery merchant Susan Brenner has a message for real-estate mogul Donald Trump: in the Windy City, she’ll do the firing.
[T]he copper-maned mogul might want to tread carefully in the Chicago area, where Brenner says she has emblazoned the phrase on plates, mugs, birdhouses and other items in her suburban ceramics studio since 1997….
For Brenner, ‘You’re fired’ is a clever pun on the process of painting and glazing ceramics in her Northbrook, Illinois, studio, said attorney Marvin Benn.”
I still think that Pixar should claim the trademark.