Porcupines in search of salt sometimes live in human places, eating plywood cured with sodium nitrate, certain paints, and tool handles, footwear, clothes and other items that have been coated in salty sweat. Porcupines like going near roads in areas where rock salt is used to melt ice and snow, and are known to gnaw on vehicle tires or wiring coated in road salt. Salt licks placed nearby can stop porcupine damage.