Many of the old folktales - as well as the new modern day experiences - show us reasons why people feared and respected the Good People. Living side by side with the Otherworld necessitated not only the wisdom to know how to properly interact if you happened upon Themselves, but also created a wide array of methods to defend against those with malicious intentions and those whose idea of mischief was best avoided. One of the main ones recommended in folklore as well as today is iron.
There are several ways to use iron to protect yourself and your home from fairies, if it's needed. Lady Wilde suggested protecting infants from being taken as changelings by sewing a bit of iron into the hem of the child's clothes (Wilde, 1888). Another commonly recommended protection for children and babies was to hang a pair of scissors, opened into the shape of a cross, above the cradle (Briggs, 1976). A horseshoe can be hung up over the door way, points up, which not only acts to ward off fairies but is also said to draw good luck. An iron knife or cross is also an excellent protection, either carried or hung up above the door or bed (Briggs, 1976). In Welsh belief a knife, particularly of iron, was so effective a protection that should friendly fairies visit a home all knives were hidden from sight lest they be offended and if a traveling person was attacked by the Fey he had only to pull his blade for them to disappear (Sikes, 1880). Another method found in Germanic and Norse traditions is to hammer an iron nail into a post near the doorway or alternately part of the door frame. Additionally it is said to be as effective to draw a circle using an iron nail or knife around what you want to protect (Gundarsson, 2007).
A more modern, but still useful method, is the use of iron water. Fill a small spray bottle with water and add iron filings, iron dust, or a piece of iron, and allow to sit for a few days. The water can be sprayed into a room or around the home as needed.
As always keep in mind that the use of iron will not effect all fairies, as some - including mine fairies and house fairies - are not bothered by it. For those that are sensitive to it, though, it is a superlative protection.
|Antique iron keys|
Those who seek to connect with or encourage the presence of the Other Crowd or spirits must be very cautious about using this metal, as it will drive away those sensitive to it. One should never, for example, cut a plant to be harvested for magical purposes with an iron knife as this will drive away the plant's spirit. We can see this belief illustrated in Pliny the Elder's description of the Gaulish Druids harvesting of Selago (Bostock, 1855).
True forged iron is hard to come by these days and although it is the best protection steel will also work in a pinch. Steel, for those who may not have known this, is still about 98% iron with only 2% or less of alloy metals added so it can still work as iron would to protect against fairies. Generally the type of item isn't as important as the material in this case so anything made of iron that you can procure can be used for protective purposes. Its also best to remember that fairy is a general term, like animal, that applies to a wide array of beings. Iron is recommended as a superlative protection against faeries, but there will always be those who are not bothered by it. If we were to say that about 80% of fairies can't bear the touch of iron then the other 20% have no problem with it, and those would include mine faeries, forge spirits, and some house spirits; basically any fairy that would naturally exist or dwell near iron or iron ore. Also any of the aos sidhe connected to smithing don't seem to be bothered by iron.To summarize; ultimately the amount doesn't seem to matter as long as the content is iron. The shape is also not important although it is more often recommended in a form that is sharp - a knife or nail - or combined with a holy symbol like a cross. The placement is best either on the person or very close by, especially near where they are sleeping. When placed above or next to an entrance it is believed that the presence of iron will keep out any Otherworldly beings. Although in today's world iron may be more difficult to find steel is fairly easily obtained and will work as well.
Gundarsson, K (2007). Elves, Wights, and Trolls
Wilde, E., (1888) Irish Cures, Mystic Charms, & Superstitions
Briggs, K., (1976) A Dictionary of Fairies
Bostock, J., (1855) Pliny the Elder the Natural History
Sikes, W., (1880) British Goblins: Welsh folklore, Fairy mythology, Legends, and Traditions