Straightening Bent Levers.

So you dropped the bike?
And the levers took the hit. Well, as long as they aren't snapped clean off, you might be able to save them. 
I'm concentrating on aluminium brake, clutch and gear levers for this post (I'll mention steel at the end).

Aluminium (Al) is light, corrosion-resistant, and can easily be cut, drilled, machined, polished etc. It can also be worked (bent or shaped) relatively easily if you treat it the right way. But it will work-harden, which means the more you bend it, the harder, and more prone to cracking, it becomes. Hence why they normally snap in a spill.

Why can't I just bend it back?
Hey, you might be lucky. A slight bend may go back easily enough, but I don't recommend trying it without annealing the part first. And it's such a simple process, you'll be glad you spent the time doing it properly.

Tools
1) Blow lamp
2) Soap, yes really.

If you've ever needed to bend steel, using heat, you'll know it needs to be cherry-red to allow it to move easily. But you don't have that luxury with aluminium; it won't change colour, and excessive heat will just melt it (660.3˚C). Which is where the soap comes in... so, without further ado.