Getting a dent out of the roof of a car is near impossible to do from the inside. The best way is to use a plunger and a ladder. Removing dents yourself can save you money, and help you brush up on your auto repair skills.
Set a ladder up on the side of your car close enough that you can reach across the roof of your car.
Dampen the bottom of a plunger and climb up the ladder with the plunger.
Place the plunger completely over the dent and slowly push down, allowing all the air to escape from the plunger.
Pull the plunger up quickly to release the dents in the roof of your car.
Carefully apply dry ice to the dents as an alternative to the plunger. While wearing gloves, hold the dry ice on each dent for a couple seconds then release it. Repeat this process until the dents have completely pulled out of the roof of your car.
Never touch dry ice with your bare skin; it can leave burns.