In the day foreign cars used to come shipped from overseas trips with that stuff sprayed all over the sheetmetal, joints, and undercarriage.
Man what a PITA (!) it was to wash and remove that stuff as part of the dealers overall PDI (pre-delivery inspection) process.
One of my first jobs in the auto business was doing this job, removing cosmoline as well as for those buyers that opted for it drilling holes int he sheetmetal and spraying it up into rocker panels as an anti-rust weather treating method.
Messy as hell and tough to remove even with specialized solvent.