In a well-ventilated area, apply a thin layer of Multi-Use WD-40 on the inside and outside of your gourd, wearing safety goggles and a mask to protect yourself during this process.
Since WD-40 is flammable, don't place real candles inside the treated pumpkins. Instead, use battery-operated flameless tea lights to safely illuminate your creation.
The chemical nature of WD-40 means that the pumpkin should not be placed in the compost bin after Halloween. It should be disposed of according to local hazardous waste guidelines.