iT’S ALUMINIMUM FOIL and it could be the cap on a plastic or even glass bottle . Which could disolve while putting it together and if the ingredients aren’t right can blow up while being made. BTW “tin” foil was usually lead not tin I don’t think it ever was made of tin and was common prior to WWII.
Alright. I never mentioned any type of foil, or any ingredients for that matter, as my info came from our local newspaper, which chose not to tell what went into the things. I had no idea what they were made of or not made of prior to this post. I think you may have hit reply to the wrong post. :)
On further research, yes, aluminum foil.
The flyer they are handing out reads tin foil and I transcribed directly from that...