Also, I was mostly curious as to why they chose bottle caps as a means of determining value. Bottle caps are made of steel and are magnetic. Can't really tell what type of alloy steel though. It can flow an electrical current however not as good as copper. There is usually a small amount of plastic underside each bottlecap, so I guess a small amount of polysterene could be used for something. Maybe if you collect enough of it you can turn it into a fuel source.You can mend small bottlecaps into little things like make shift arrows. But I feel like it'll be pretty difficult to burn up to about 2500 degrees Fahrenheit ( 1370 Celcius) burning wildlife to melt steel so you can shape it. In a good campfire with dry hard wood you can reach up to about 1000 degrees celcius. Aluminum melts at 660 degrees celcius so I'm pretty sure aluminum would be a little easier to mend things into like blades or whatnot. Glass would melt at 1000 degrees celcius so you can probably make something out of that. But I can imagine it being a little difficult to reach upwards of 1000 degrees unless your making a huge fire.
I have a bottlecap in my hand and I'm trying to think what I could possibly do with it. Not much once you get down to it. I'd rather have other metals like aluminum and copper. Preferably copper because it can melt at around 1084.62 Celcius. It'll be easier to melt this down into wire or other uses. Lead would be extremely useful with a melting point at only 327.5 °C which could probably melt with a small fire.
You could reverse engineer the magnetic quality and build a makeshift electromagnetic induction generator for small bursts of volts but that would require an important earth metal, a magnet.
