I just made my cat a toy and stuffed it with foil. Kind of like Bella Boo said, but I used a wrapper from a breakfast bar. The metal foil stuff. Never thought of a chip bag! LOL! I have plenty of those around. The cat likes it. (It's also got catnip in it, though, so maybe he just likes the high. Silly addict cat.)
I have thought of doing this before for a baby blanket, but never did- you will have to tell us how it turns out.