I came across several interesting bits in the book The Etruscans outside Etruria by Paolo Bernardini and Giovannangelo Camporeale. There is speculation in this book that the Etruscans contributed salt to the trade economy for wine in particular.
Salt was another of Etruria's great resources. It was either mined, as in Volterra, or extracted from seawater in evaporation ponds that were set up along the Tyrrhenian coast. Between Ostia and Pisa the location name Saline is often found, a name testifying to an activity that had extremely ancient roots in the area. Indeed, wars between Rome and Veii that date back to the time of Romulus were fought over the possession of saltworks, which were quite productive near the mouth of the Tiber.
The role of salt in the greater economy must not be overlooked, though its traces are mostly hypothetical. Salt would explain the arrival of a substantial quantity of Euboean (Greek) pottery in Veii and Rome during the eighth century; sources date the wars between these two cities over the possession of the saltworks at the mouth of the Tiber to this same period.
Pythagoras was pretty keen on salt too: "Salt is born of the purest parents: the sun and the sea." He also said that "salt was the emblem of justice; for as it preserves all things and prevents corruption, so justice preserves whatever it animates, and without it all is corrupted."
Hippocrates lauded the use of sea water and salt baths for healing, as did texts from ancient China. Ghandi began the non violent revolution against Great Brittain with the Salt March. In short: The Brits controlled salt production and made it illegal for anyone else to produce it, even for themselves. You can read more about this on the holy wiki.
From The folklore of common salt: http://www.sacred-texts.com/etc/mhs/mhs32.htm
In Sicily, too, it is sometimes customary for the priest to place a little salt in the child's mouth at baptism, thereby imparting wisdom. Hence the popular local saying in regard to a person who is dull of understanding, that the priest put but little salt in his mouth. A similar usage is in vogue in the district of Campine in Belgium. The use of salt at baptism in the Christian Church dates from the fourth century. It was an early practice to place salt, which had been previously blessed, in the infant's mouth, to symbolize the counteraction of the sinfulness of its nature.
Here's a Roman folk tale called The Value of Salt
Enough with the history lesson! Let's get to business!
Salt protects. It was used in mummification and in meat production to preserve. So wouldn't it protect metaphysically too? One of the things we look to when we commune with The Horned God is protection. We wear a horn. We flash the mano fico. This highly valued, magical protection powder we are talking about now is white and salty. Have I drawn enough of a picture? No? It's divine spunk. There, I said it. The preserver and protector in mineral form. A man's ejaculate is a reflection of the divine male spark. Salt is the stuff of life. Marry it with the waters of our mother's womb and there we have the primordial ocean from which Love herself, and life sprang forth. Too much?* After my Priapus post you know we don't shy away from these topics here :)
Many magical traditions use salted water representing the union between male and female, the ultimate means of cleansing and preserving all in one. Salt in the corners of the room repels negativity. Salt before your door will negate anyone or thing trying to bring evil into your home.
Aside from constantly tending the fire, the other main job of the Vestal Virgins was to make the Mola Salsa, the salted cake. It was used to purify sacrifices and alternately burned as an offering. I find it interesting that this tradition was introduced by Pompilius, the second King of Rome, who happened to be Sabine. The cakes were less like KFC biscuits and more like, say wafers. Also interesting is the fact that many nunneries used to produce the communion wafers.
The salt and grain was, and is, used to purify a space. In modern times, when moving into a new home, bread and salt are brought in to ensure protection and prosperity.
Don't want someone to return to your home? Put dash of salt in their shoes. Can't get their shoes off surreptitiously? Throw the salt on their tracks as they leave.
Salt can be used to delineate sacred space aka cast a circle.
You can trace sigils in salted water to root protection wards on your body or property or windowsills. Keep some in a small pouch in your car, tied with a red ribbon.
We haven't even gotten into the uses of black salt yet! I'll direct you to Lucky Mojo who has a whole page on the uses of salt. http://www.luckymojo.com/salt.html
And don't forget: *Take these blog posts with a grain of salt ;)