A roaster bowl is a bowl of weed that you pick out of the ashtray. Usually when you cash a bowl there is still a little bit at the very bottom that isn't burned so you end up with a bunch of roughly pea-sized charred nuggets that can be smoked in times of famine.
"Damn I burned through that whole bag last night. I'll have to scrounge up a roaster bowl."
by ShaneWood January 08, 2012