What's it worth in bent and unbent condition? If it's not worth much if anything bent, I'd try to straighten it. Don't use anything hotter than a standard propane torch or you might accidentally melt the thing. I think I'd start by boiling it first and see if it bends easily or not. Maybe use a piece of hardwood to pry with. Anything metallic and you're likely to damage the surface. Once you get the bend more than 90 degrees, you can probably use a soft jawed vice to flatten it out the rest of the way.....maybe not perfectly but at least presentable. Handling it while hot might take some thought. In water, I have a rubber coated pair of forecepts but that wouldn't work well with a torch. Maybe sandwich it in between two pieces of scrap aluminum can and grab it with needlenose vice grips? Which ever method you use, work the metal SLOWLY. If it feels like it's going to crack or deform you may have to give up and accept it the way it is. There are people in the business of restoring automotive aluminum mouldings but unless this thing is worth quite a bit, it wouldn't be worth the cost to have it done.
