[ChevLoRay]

Wonder if he was just usin' a mixture of kerosene and used motor oil? Think about all of the old dirt roads that used to exist and what a mixture of oil and dust looked like. I've seen my share but the oil got there because of the leaking seals and the oily vapor from the road draft tube.

I guess it was an early undercoating, whatever the mixture may have been. Kerosene or Varsol...either one is thin enough to get into nooks and crannies if you sprayed it. But I'm gonna guess that some of it just got mopped onto the bottom of the chassis and floor pans.