2.0 Straightening Outer Skin

WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.

"Cold" straightening: Press dents out from their center and smooth in an outwards direction with gentle taps.
In the case of small, soft dents (hail and parking damage), this is also possible without damaging the paintwork. This work requires a special tool and a trained employee.
"Hot" straightening: Heat dents in their central point only with a gas flame or hot air blower. Then quench the material with a wet cloth. Heating can only be detected by a curvature of the material. The color of the material does not change.
In the case of damaged areas which are only accessible from one side, stud welding can be used. The aluminum bolt welded on in the center of the damaged area is beaten out with a hammer until the dent is eliminated. The bolt is then ground off.
Avoid notching and cracking.
Avoid hardening and overstretching.
Avoid heating and excess temperature the outer skin over large areas.