Burn scrap nothing, In Colonial America they'd burn decrepit houses to get the nails. Enough that colonial governments passed laws against it.

Which reminds me when I was a little kid people would carefully pull the nails out of old boards and save them.

I did too. These days, I save nuts and bolts. Not because they are expensive to buy, but I don't want to spend a couple hours going to the hardware store to get one.

I thought everyone had a container where they keep a random selection of nuts and bolts that have been collected over the years...

I have two clear plastic drawers from a refrigerator I had 15 years ago almost overflowing with extra hardware. While it’s mostly just nuts, bolts and nails I also throw any extra part that comes with random widgets. I just dug through it yesterday to find two small machine screws to tie together a broken plastic connector. It’s not hoarding if you use it right?

Yeah, I have a tub with random springs, brackets, spacers, clips, and odd metal bits pulled off of devices I threw away. It's surprising how convenient it is when you need something.

That's wild! I thought nails were way easier because you could maybe just cast them. I guess forging would make them substantially stronger.

Casting parts like that is actually incredibly difficult. The iron will want to freeze before filling the mold cavity, since the cross section of a nail is so small. While tedious & time consuming, hand forging a nail is significantly easier than attempting to cast one. Plus, cast iron is much more difficult than forging simply due to the much higher temperatures required. A simple charcoal fire is adequate for forging, the higher temperatures required for casting necessitate specialized equipment. Hence why many village blacksmiths didn't have the capacity to produce cast iron parts.

Oh interesting! TIL, thanks!