I've done this. It will work on smaller dings like hail damage. The trick is to do it at night. Use a hair dryer and heat the area for 45-60 secs and immediately apply the dry ice. It should pop out. The reason for doing it at night is that if you take the car into direct sunlight, the heat may draw the ding back, especially in the summer heat. I've read about the compressed air trick, and plan on trying it soon with a couple of hail dings a got recently. Hope that helps and good luck!