Daath
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well the thing is is oil is in way more than just the machine joints, they may not need lubricant but they will need oil for something, unless something of equal magical properties is made.
I watched this crazy guy on this documentory called, collapse he kinda crazy but he talks about all the things oil is in, and some of the shit oil is needed to make is insane.
if your into conspiracy and end of humanity and fall of governments, collapse may entertain you. they guy does come off as a little crazy though but alot of what he says can be fact checked, and some his solutions, were just mention by the president on his last address to the country, as things that need to happen to secure americas future.
Even if crude oil is irreplaceable I'm sure machines that have passed us on the evolutionary ladder would have no problem utilizing, recycling, maybe even producing these materials.