Leaded gas is still used in small airplanes with internal combustion engines. If you live near a General Aviation airport you are being showered in lead so some rich guy can play pilot.

They knew you could, but mostly didn’t because it takes a ton of energy to boil off water. There was no petroleum, no coal, so you would need a bunch of wood. So you use a bunch of wood to boil a liter of ocean water and you would get about 35 grams of salt. It just wasn’t worth it.

How do you think they train the models?