I like your idea of breaking up this topic into categories, Michael. We've had many similar threads over the years but not all of them have ended up listed in the Thread Map.
The most recent similar thread is
unusual treasures for scroungers/barterers to find.
Another, slightly less relevent thread example is
The Value of Precious Stones
If you have a look in the
Thread Map you'll see a number of threads that might contain some of the sort of information you're wanting to include in this thread, at least obliquely.
For example,
Salvaging Fuel and
Recovering liquids from junked vehicles.