I don't know about the salt shaker ( salt pulls moisture out of the air
only up to a point), but be cautious with your Camelia oils. Natural oils
will tend to crosslink over time upon exposure to reactive gases in the
atmosphere and get sticky and gum up stuff, and I wouldn't use those
natural oils (which are always combinations of various chain lengths and so
on) on sensitive measuring tools ( especially tools that you basically
have to disassemble to clean, using ultrasonics and special cleaners).
Much safer to use instrument oils designed not to turn into varnish.
Cheers from Waterloo