After a LARGE hailstorm here I was told dry ice would remove the dings. I figured I had nothing to loose so I bought a pound. I studied several You Tube videos. I first tried the hair dryer. No change. I then moved to a paint stripping heat gun. The dents did not come out and I was very worried about doing damage to the paint.
So...I gave the dry ice to my kids and they a LOT of fun experimenting with it so it was not a total loss.
Short version...it does not work.