Green’s Dictionary of Slang

(drugs) cocaine.

1984		in N. Stone et al. Cocaine: Seduction and Solution.
1989		(con. 1982–6) T. Williams Cocaine Kids (1990) 15: When he felt a cocaine shipment was unique – ‘Peruvian flake,’ for instance – he would call to ask if I wanted to see it.
1989		C. Hiaasen Skin Tight 256: Your bartender just tried to sell me two grams of Peruvian.
2001		ONDCP Street Terms 16: Peruvian [...] Peruvian flake [...] Peruvian lady — Cocaine.
2012		M. McBride Frank Sinatra in a Blender [ebook] He’d break out the Peruvian nasal therapy and he was guaranteed a blow job.