TL;DR: is there something I can coat the inside of metal salt shakers with to protect them? Or am I missing a better clue?
I have two pairs of antique glass salt shakers (of significant sentimental value) with domed chromed tops, which are deeply corroded on the inside.
I've been unable to find modern shakers with matching tops to swap in (I've found a lot of shakers with chromed plastic tops, but not the right size and shape), so I'm slowly cleaning off the corrosion with vinegar, ketchup, and gentle elbow grease. (It appears that the inside was either unchromed base metal or the chrome has corroded away in places, but I'm not done cleaning yet.) (I know that other products such as ammonia and limescale remover are also recommended, but I'm sticking to gentler methods if I can.)
Assuming that the metal is structurally sound, is there a way to protect the tops so that they are less prone to corrosion? Is this something a silversmith could do for me? (I assume that invoking a professional would cost more than buying replacements.)