To illuminate a carved pumpkin, string lights are preferable to candles for most designs: Wrap a strand of 20 lights around a glass jar, and secure wires with tape. Cut a hole in the hollowed-out pumpkin for the cord, and place jar inside. Unplug lights before leaving the house or going to sleep. If using a candle, place it in a glass or votive holder, and cut a hole in the back of the pumpkin for ventilation (or leave the top off). Battery-operated candles are another good alternative.