Why are iron, salt, and other minerals thought to repel

Look at me.

We >>>/x/ now.

>>936816
They are rare/valuable commodities. Also salt preserves and purifies food and iron is used to make steel, the idea they change and purify things.

>>936816
Disease had, in many cultures, been thought to be caused by malicious spirits.
Disease is instead usually caused by some variety of microbial colonization or from toxins created by microbes.
Salt and minerals like silver create conditions that inhibit microbial growth.
This inhibition reduces instances of disease among practicing humans.
Thus, "malicious spirits" have been warded away by the use of such items..

>Iron

Dafuck is this weird shit Hregs made in the forge? It's like man triumphant over the forces of nature
>Salt
Interesting, this stuff can keep stuff from rotting. It's pure, like little particles of anti-death/evil.

>>936833
>how dare you explore the evolution of common human beliefs

>>936852
I tought salt wasn't well known for its conservative properties until napoleonic times

>>937153
Salting meat has been around since at least the Romans. I think you're thinking of canning

>>936816
>Iron

Sometimes magnetic, imagine you don't know what magnetism is and you see this chunk of metal or rock moving around on its own. Like, holy shit, it's all true just like Han Solo said

Because each could be peddled to fools for coin at some point

I thought Japanese Oni were repelled with setsubun beans

>>936816
Because they're rare or uncommon in those periods and if it was something freely available (a handful of grass), then a side industry can't form out of it which preserves itself.