slack wax - a semi-refined wax, distinguished from scale wax by having a generally higher oil content. Slack waxes with oil content below 10 mass percent are used for manufacture of religious candles, as a feed stock for chlorination processes (see chlorinated wax), and in non-critical paper making applications. Slack waxes with higher oil content are used in the manufacture of building materials, such as particle board. See oil content of petroleum wax, refined wax, wax (petroleum).