Weapons of A-Salt

Salt has an interestingly mundane place in Dungeons and Dragons. 3E doesn't make use of it too much, outside of a Wall spell, a Transmutation spell, and an equipment entry that says it is worth about 5gp per ounce. As far a I know, 4E doesn't mention salt at all, 

Here in the Philippines, though, salt is the bane of just about every mythological creature. Find the lower half of manananggal, spray salt onto the open wound, and either the manananggal cannot reform in the morning, or her lower half outright melts, depending on the story. Salt can be used to bind ghosts, sort of like a Magic Circle. Any food offering to the diwata (fey) would be offensive if it contained salt for flavoring. 

A friend of mine told me that salt is an aversion to Celtic fairies, as well. So why is salt such a non-item in D&D? We are probably biased by modern sensibilities: Salt is such an inconspicuous, everyday item these days that we forget how hard it used to be to procure. In some sense, 3E at least remembered this. Look at its price - in a system where commoners took home an average of 3gp/month, it's interesting to see salt at 5gp, which is the exact same price as silver of the same weight.

Ask Lot if salt is no big deal and he'll probably be pissed.

So, if we want to include some of the more mystical properties of salt in a game, how would we go about it? Here are a few quick ideas:

• Salt can hurt someone's eyes, but throw a handful at a fey, outsider, or non-elemental spirits and it'd actually deal damage that overcomes material and magic-based damage reduction.
• Alternatively, throw it at incorporeal undead and it'd become physical for a short amount of time.
• Salt can be used as material components for magic circles. It can act as a grounding agent for magic, in that it can suppress some minor magical effects.
• Salt, however, is mundane and will only inconvenience (won't completely stop) more powerful spirits. If you're binding a marilith, for example, using salt for your magic circle might turn out to be problematic. 
• If you want to have a salt-like substance that packs more punch, take a page out of Trese's book and use ground-up mermaid bones. And you thought necromancer skills were only useful in graveyards. 
• Fantasy salt is an element: It doesn't hurt elementals.
• It might work on some shadow creatures. If you want to be sure, throw it at a manananggal and see what happens. ;)