These are some zippered pencil cases or makeup pouches I made from cool Halloween Candy bags. The Witch bag won third-place prize in the DIY Halloween Contest (in the green category).
http://www.instructables.com/id/DIY_Halloween_Contest_Winners

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If I want to make something form a foil lined bag, I use a technique where I sandwich it between fabric and clear vinyl, and sew the item that way.
Heat is never used in the process- it's just sewing.
You can see an example here:
http://www.flickr.com/photos/eclipse_etc/3461699016/