Employers in Smith’s day often lacked coin to pay their workers; wages could be delayed by a year or more; in the meantime, it was considered acceptable for employees to carry off either some of their own products or leftover work materials, lumber, fabric, cord, and so on. The nails were de facto interest on what their employers owed them. So they went to the pub, ran up a tab, and when occasion permitted, brought in a bag of nails to charge off against the debt.
