Good article, but I disagree with you about precious metals, jewelry and coins. Since the beginnings of societies and civilizations, people traded precious stones, sea shells, jewelry, copper, gold, silver, and any type of coins or medallions. For the thousand years before the discovery of fossil fuels (which led to the growth of everything) the go-to currency was coins (particularly bronze, silver and gold). I would not really recommend gold since it is simply too valuable, but I think low denomination silver coins will be of enormous value in a collapse to trade for some apples, a bucket or a shovel.