Supposedly, though, ghosts are frightened by salt... but why should that be? And is it true? Or is this just another superstition that, upon investigation, lacks the verisimilitude we grant it at first glance?
Interestingly, I found some research suggesting that you can actually SELL salt to ghosts in a cemetery and they'll give you "Hell Notes" in exchange; those cemetery dwellers are using the salt for cleansing purposes. If the procedure for such a sale is followed correctly, said Hell Notes turn into real cash. Personally, I'm going to keep my day job. But this legend comes out of Singapore, as far as I can tell, suggesting that the salt superstition for ghost repellent is NOT universal, although the idea of salt as a purifier/cleanser seems to be!
When I thought of ghosts and salt, I immediately thought of the saying, "Spill some salt, throw it over your shoulder, or you won't live to be much older!" I thought this might be a good place to start to help me find some answers about ghost repellent. According to superstition, if you spill salt, you are to throw some over your LEFT shoulder to get the devil to back off. And hey, if the freaking Devil is afraid of salt, surely your run of the mill ghost ought to be too, right? Sure, why not?
But why the superstition in the first place? It seems, according to my research, to be historically rooted in salt's expensive origins. Wasting salt was a faux pas, and while I can't find any evidence to support THIS idea, perhaps tossing some salt says, "Big deal; I can afford more." At what point, exactly, people went from chastising those who spilled it to throwing it over their shoulders, though, remains unclear.
Salt gained popularity religiously for several reasons: it's a symbol of purity, and it has healing properties. Several modern religions still use salt in ceremonies; personally, I use a diluted salt solution to clean new piercings. It's intriguing that spilling salt is supposedly even used in Da Vinci's "The Last Supper": betrayer Judas is pictured having just spilled salt. Bad form, Judas, bad form... but we get a picture, forgive the pun, of both the faux pas and the devilish symbolism.
So salt has symbolic properties for purity, and supposed spiritual healing properties. Blessed Salt, then, is a common tool among ghost hunters involved with dangerous hauntings. The research I did suggests a blessing from a Catholic priest, but I'm willing to bet that rabbi-blessed salt would be just as effective - but good luck getting a rabbi to bless that salt! Why any blessing is necessary remains unclear, except that it would be necessary to "charge" the salt with its (not-inherent?) protective powers.
The religious use of salt plays into use of salt as ghost-repellent for the reasons above, but some have purported an alternate reason for salt's effectiveness. According to folklore, ghosts love to count, but apparently aren't very good at it (Haitian folklore also suggests that ghosts are quite easily confused by strange designs and upside down windows, amongst other peculiar things). By leaving grains of salt out, ghosts will supposedly give up trying to count them after a few days and leave your home. In this case, I'd have to say being a ghost would really stink if all my endeavors were so Sisyphean! "Must count salt grains... 1, 2, um, ..., 76... Dang. I'll start over. 1, 2, 3, ..., 42? Ugh! Must count salt grains... 1, 2, ... dude, this SUCKS!"
So here's the research summary:
1. In Singapore, and perhaps elsewhere, you can actually sell a ghost salt; best get-rich-quick scheme I've heard in a long time. Also, ghosts get dirty.
2. The devil is afraid of salt. Ghosts, by proxy, ought to be, too.
3. Spilling salt is bad form. Spilling it over your shoulder is okay, though!
4. Salt is pure, and is good for soaking a sore piercing... or a soul.
5. Ghosts. Can't. Count.
So, is there any real evidence to suggest that a ghost should be afraid of salt, and that, as a result, we shouldn't expect to find the Raymond Robinson lurking in his tunnel, now occupied by the rock salt of SPPW? Nope. Not really, at least not in my opinion. Whether we manage to find him, or any other paranormal activity out there, though, remains to be seen!