The average clunker contains about a half kilo worth of cerium and neodynium, that is not negligible in aggregate by any means. More modern fancy cars can contain several kilos (electric cars average about 5kg from what I recall, depending on battery type natch). I think you're both misunderstanding how catalytic converters work and totally whiffing on how many random spots in a car use a magnet for something.
Biting the hand that feeds IT
