Green’s Dictionary of Slang

(N.Z. prison) the lowest quality of marjuana cigarette, sometimes filled with reused material.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 161/1: scummy-scum n. a skinny, meagre marijuana joint of the worst quality, sometimes filled with reused marijuana scrapings (the remaining scraps not smoked in the previous joint).