Mostly "brick weed" or weed that is dense and extremely compacted. Most bud smokers like fluffy weed.
-I grabed a snacth offa Jim the other day, and found out that it was Dirty Thirties, and i payed for dro.
The expression almost always refers to women, as men are thought to always be in this state.
"Alright Ladies, this dirty thirty is on the house!"
Leo: No, I can't drink, there are exams this week.
Jimmy: No, I mean the dirty thirty from Nafer.