In a post-apocalyptic world, would plastic be more useful than metal as currency?

Question

What would be more valuable in a post-apocalyptic world and/or more suitable to be used as currency: plastic or metal bottlecaps?

The Fallout video game series popularized the use of metal bottlecaps as a form of currency in a post-apocalyptic world as they are, supposedly, difficult to forge. However, wouldn't it be more difficult to assemble the tools for plastic injection moulding than metalsmithing? Thus forging plastic bottlecap currency would be more difficult, not to mention the ubiquity of plastic bottlecaps means they'd be more common (scarcity is probably not something you want for a medium of trade).

On second thought, I considered the fact that the imitation-proof quality of the proposed currency would most likely be pointless as a post-apocalyptic society would probably not use a fiat currency, the value of which is derived from the government, but revert to some form of barter-and-trade where the selection of a common currency of exchange would be more dependent on its inherent value than any government fiat. Would then the currency be metal bottlecaps, which have more utliliarian value since they can be melted down be used for other purposes?

Answer 1

For starters, why do you need plastic currency? I mean, if you wanted a meaningful currency why not just use already-forged money as stated in other answers? If you really insist on this plastic currency I feel the need to keep you informed.

MELTING TEMPERATURES

The following are the melting temperatures of several currency alternatives

• Iron-2,800°F (1,538°C)
• Plastic- Wikipedia article on plastic:120 to 180 °C (248 to 356 °F) or 105 to 115 °C (221 to 239 °F) depending on the grade.
• Gold- 1,948°F (1,064°C)
• Silver-1,763°F (961.8°C)
• Bronze-1742°F(950°C)
• Copper-1,984°F (1,085°C)
• Tin-449.5°F (231.9°C)
• Titanium-3,034°F (1,668°C)

A BRIEF HISTORY and LIKELYHOOD

• Iron- A brittle conductive metal that has been used since the dominance of Ancient Rome thousands of years ago for a variety of things. Is now used for even more things (as a matter of fact trying to list them all is quite pointless to this answer). Just know that it is one of the most abundant of the well-known metals
• Plastic- Yep, that material that your water bottle is made out of does have some potential as currency in the short term. Since oil is required to make plastic you would have to have working oil rigs and access to industrial factories. After a global apocalypse some of the first things to go would be oil stocks.
• Gold- The oldest currencies were made out of this and it is quite likely that our final currencies will be made out of or based on this. After an apocalypse the soon-to-be-worthless computers will be stolen by a bunch of criminals. They will end up inheriting the earth because of the small amounts of gold in them and the large number of computers to be raided. This is one of the rarest minerals on Earth and as such is one of the most valuable to possess. I would imagine after we begin to return to currency the first new coins will be forged from this.
• Silver- This is pretty rare. Silver is very valuable. As a matter of fact, it saved Denocracy! Yep, the Persians were gonna invade Greece and the discovery of a new silver mine gave Athens the money she needed to repel the Persian naval forces and build a Greek empire under the guise of the Delian League…..why would things be any different?
• Bronze- A mildly strong alloy. Has some potential as currency but is more widely available than some of the others
• Copper- MAYBE……assuming whatever town decides to use it has strict regulations and backs it up with a more precious metal like gold
• Tin-I have little knowledge of this metal. It is quite useful in the creation of cans though…..
• Titanium-An extremely strong and durable alloy. Has potential due to a rareity.
• Diamond- A beautiful gem. Is extremely hard to polish and is one of the hardest known materials (I think possibly the hardest). It is a highly pressurized form of Carbon and can come in a variety of colors, but white is the rarest. A finely polished white diamond is worth more than its weight in gold and silver. The actual problem here would be scarcity compared to other alternatives.
• Other Jewels-Notta.

Would then the currency be metal bottlecaps, which have more utilitarian value since they can be melted down be used for other purposes?

I think if it came down to it metal bottle caps would prevail, but not in the end. In the end we can know from the past that we WILL resort to gold, silver or diamond. I suppose we might use the metals and minerals needed to make computers (rare earth elements) as a form of currency----or at least to back our currency. This is, of course assuming that we aren't total idiots and don't lose most of our current knowledge to make computers.

Answer 2

Scarcity is part of currency In trade, you need scarcity. In trade, you exchange something which has value for you and get something what has value for them.

So, generally, step 1: Getting plastic should be relatively hard. In postapocalyptic world, people controlling landfills (full of valuable plastic) would be really rich, because plastic would have a value in your world

You need strong authority accepting plastic as payment: It boils down into who accepts what. Barter-and-trade would be still pretty in common, but also you would be willing to accept bottlecaps or plastic pieces simply because Brotherhood of Steel accepts them.

In realistic post-apocalyptic world, such authority would be probably military based. They have valuable things to offer (weapons and ammo) and if they accept plastic (for whatever reason), then plastic can be universally accepted tool of trade, because you know, that in worst case, you can buy ammo from the Brotherhood for plastic and barter ammo for food (if food owner is silly enough to not accept plastic in first place)

Answer 3

As Burki said, currency is just a way to make bartering easier. You take something with a limited supply, and use it in place of goods. Say I have a goat, I will give you my goat if you give me 100 glass beads, because I can take those 100 glass beads over there and trade them for 14 chickens. If someone makes a glass bead factory and starts spitting them out by the thousands, my beads aren't worth anything, except as a really short necklace.

Most currency has no value in itself, it's just a symbol of value. There is a possibly of giving the symbol it's own intrinsic value, and plastic is actually really good for that. Say, I have a goat, I will give you my goat for 100 plastic ingots, because I can take them over to the guy with a 3D printer and make a tool that I can use to earn/trade for more plastic. In that case the 'money' is valuable by itself, and would be somewhat more inflation resistant.

If the mechanism for manufacturing new plastic from oil is missing, then plastic mining would be huge. Actually, landfill mining would be extremely profitable for a lot of reasons: metals, electronics, plastics, etc.

And most landfill locations are known, so they would become fortified towns where people would come and excavate for pay, like the gold/coal mines of old.

I can also see people with access to boats going out to net the floating garbage islands in the ocean for their resources.

Answer 4

The reason to use money as a general trade good is flexibility. If i have a chicken and need a shovel, But the guy with a shovel needs a bucket, money is more convenient than finding someone who will trade my chicken for something i can trade for a bucket to get me the shovel i needed in the first place.

In order for a currency to work more or less reliably you need a system with little to no inflation, lest you end up with a situation like in post-WW1-Germany, where you needed to spend what money you had asap because it would be mostly useless tomorrow.

This means that scarcity of the currency is vital.

Concerning your original question: most plastics are thermoplasts, that means they can be melted. Duroplasts on the other hand disintegrate when heated, much like most organic material, so they require a solvent to liquefy.
The melting point of all thermoplasts i know of is much lower than that of most metals, so it would be easier to liquefy any plastic you fould, and pur it into a form to coin your own money.

So, i assume that a metal based currency would work best.
About the bottle caps: Why not just use the coins we use today? I think it is safe to assume that lots of coins will survive, and the price, in coins, will have to be newly negotiated to match the availability of the coins. But you would have to do the same with bottle caps, so i guess that should not be much of a problem.

EDIT

Not all plastic is made from mineral oil. Some of it is made from sugar or starch. And that is much cheaper and easier than mining, smelting and coining metals.