Watch this video and see an amazing way to repair a car dent using only dry ice.  Apply the dry ice to the dent for a few minutes and then let the surface warm up.  The dent pops back out automatically! The dramatic change of the surface temperature causes the metal to contract and expand. Right before your eyes you will see the dent literally pop back into the correct position. Dry ice can be found in most supermarkets and fishing supply stores.  Be careful handling the dry ice, always use heavy gloves to prevent freezing your skin on contact.