Yes, Colin, sodium chloride plus iron and steel (and any other metal for that matter)
bad, my tongue
OK . IIRC, you're a professional chemist...
In the days when felt-tipped pens
usually had ink based on chloro-carbon solvents, the company I worked for went to great lengths to find pens which were chloro-free (for writing on piece-parts), out of concern about corrosion.
B