Stacks of macks have replaced packs of smokes in the underground economies of federal prisons, the Wall Street Journal reports. Inmates, barred from using cash, use cans of mackerel from the prison commissary for everything from gambling to buying hooch to paying for legal papers. The going rate for a haircut is two "macks," ex-cons report.
The cans—or pouches—of the oily fish took over as the coin of the realm after cigarette sales were banned in federal prison in 2004. Unlike the pricier cans of crab or tuna, few inmates are interested in actually eating the contents. Enterprising cons can amass whole lockers of macks—which they try to offload quickly when their release dates approach.