Quote Originally Posted by E. von Hoegh View Post
By that, they mean what used to be called "white gas" that is gas with no additives, straight distillate.
The term petrol and gasoline in a 1957 translation from Gauthier's German manual surely refers to the automotive fuels. the English term was "white spirit" otherwise.
At that time, petrol (as I recall, both grades) contained tetra-ethyl-lead plus other additives including upper cylinder lubricants.
I grew up in my father's auto dealership/workshop and to clean things including small parts they used half/half petrol/kerosine in a high air pressure spray gun.
Flammable and a health hazard (although those guys lived long ! ) it sure got the parts clean and probably left some lube on the surface.

I haven't opened the Prontor SVS here but from what I can see it is not up to the quality of the Graflex Wollensak ones here.