It's fun to experiment with the effects of heat from my butane torch on art materials. I can imagine all sorts of abstract applications for these materials.
Note the cool bubble pattern. All the foils bubbled.
In addition to the foils, I tried torching some other collage materials.
Piece of copper in the middle- copper changed color to a darker, duller version of the original piece
Strip of silver metal flashing (aluminum?) - This silver metal turned gorgeous shades of gold, amber, and brown tones and remained shiny. Where I held it to the flame longer, it turned dull charcoal gray.
Bottom - purple metal turned gold to silver to melting.
This is all I've torched so far. I did them outside with a bowl of water on hand for dousing the flames. I'm sure you will be seeing materials prepared this way in my future abstract work.