Well, aluminium foil seems to be a common material for in-scale scratch building.

Tins from tinned foods can also provide us with thicker foil, commonly used for seat belts etc.  

In this case this kind of foil is used for enhancing the image of the inner side of some types of jet engine afterburners. The initial idea came as I was trying to find a way to build details for a Mirage F1 ATAR engine exhaust.  

Though the following pictures are pretty self-explanatory, I would like to mention that the lighter is used to initially straighten the surface (check 2a, 2b).

Depending on the thickness of the toothpicks you can achieve various sizes of curves in order to match your case in the appropriate scale (check 3a, 3b).    

I would be glad to hear that you may find it useful!  

Regards, 

Yiannis Ladopoulos