Where can I find some glitter dust?

Hint 1 of 11:

Rincewind will actually give you a pretty big nudge when you find the glitter
you need.

Hint 2 of 11:

Celebrities are known for being glittery.

Hint 3 of 11:

Or even want-to-be celebrities.

Hint 4 of 11:

Look at the milkmaid's dress (she's in the Plaza).  That's pretty glittery.

Hint 5 of 11:

Does the milkmaid remind you of any real celebrity?