When I did it on my last car I used a heat gun, and as above to hot to touch but you still should be able to give it a tap with your fingers just to feel the heat.

Remember its always a lot easier to get more temp into it then to wait for it to cool down.

If you're planning on using a mallet you can be quiet rough before it start to bend but in reflective surfaces you will notice how even it is.

__________________
Bitches love cardigans