Green’s Dictionary of Slang

(US campus) a thing of the past; usu. in phr. I’m archives, goodbye, I’m leaving.

1984		Eble Campus Sl. Sept. 1: archives – an act or object of the past.
1991		D. Jenkins You Gotta Play Hurt 279: The oily dwarf got himself fired. Yeah. Dismissed. History. Archives.
1996		Eble Sl. and Sociability 101: I’m history, a parting phrase modeled on an underworld expression referring to death, has inspired the formation of I’m archives and I’m art.