I am looking for a salt grinder.

I know salt is an aggressive compound and it needs a little bit of attention when we design products.

Since most of grinders have plastic-made or stainless steel-made parts (I'm talking about grinder mechanism), and corrosion is virtually unavoidable,

As engineer, I have one (+bonus) question:

I know salt can corrodes metals, is it true for plastics too?

Bonus. Concerning about health, is preferable to have metal corrosion (rust) or plastic corrosion?