I bought some ectromechanicals from europe , they were filthy black with the stuff.Its definetely not the familiar carbon smell with electro,s ,but rather irritating. (I started coughing near them) ,your theory(cave) the storage warehouses in industrial areas sounds correct,my machines ,were stored for 30+ years in the same warehouse.
stored for 30 years. Now that would be exciting to open up those pieces of history. that would have been a great buzz.
Now, u can say u have 30 yr old (minimum) 30 yr old black dust. Cool. AND some really nice pins.
