Lice can't live longer than a couple of days once they fall off the scalp, so a few simple housekeeping measures should prevent a re-infestation: Launder bedding, towels, and clothing used or worn within 48 hours before treatment for lice. Use hot water to wash and the hot setting to dry. Dry clean clothing and other items that can't go into the washing machine. Vacuum carpets, rugs, and upholstered furniture; if you have a child who uses a car seat, vacuum that, as well. Put items such as pillows that can't be laundered into plastic bags and seal them for two weeks.