The following discussion, I feel is necessary for those who do not wish to have the fae in their homes. These wards are also used for keeping the darker courts at bay as well as the more mischievious of the fae. However, all fae are mischievious, they love to play pranks on humans, there is no "good fae" or "bad fae" they simply are just the fae. Plain and simple,no ifs, ands, or buts about it.
Anyways there are several things one can do to ward off the fae and keep them at bay. As you saw in Stef's thread, the fae love love love to take human babies and leave behind a changeling. These fae babies take on the appearance of the stolen child, but in reality it's a wizened old goblin or a rotten piece of wood. Up until the last century in the British Isles, midwives would protect newborns by blessing them with three drops of water (one for peace, one for wisdom, and one for purity) as they did this they would say:
To avoid thee from the faes
To guard thee from the host
To aid thee from the gnome
To sheild thee from the spectre
This method always reminds me of the 3 faerie godmothers in Sleeping Beauty...it also reminds me of Béfind, who is an Irish Faerie Godmother. Her name simply means "white lady", a title given to many female faeries. Along with two other faeries, Béfind appears at the birth of a child to predict it's future and bestow faerie gifts upon it.
Other ways to protect newborns from the fae are burning leather or bindweed in the room, hanging rowan twigs in the form of the cross over the cradle, or leaving iron in the infants bed(don't recommend). Now iron does *NOT* give the fae a severe reaction like holy water on a vampire...whatever...the fae just plain out don't like it, they despise anything modern and iron is modern in their eyes...so they avoid it.
More traditional methods can guard yourself against the fae or even just the fae's attention. Carrying or wearing certain plants: Hazel wands, rowan (mountain ash), St. John's wort, or daisy chains will keep the fae away. In France, flaxseed is spread on the floor to rid the house of goblins, in mexico it is said tobacco smokechases away the fae as well. Each culture has their own methods in keeping away the Fae, I know Saz's Slavic group has a list of these methods, and I'm sure Stef will put some of the Greek methods which would be wonderful. I know mostly Irish, Scottish, and Welsh methods mostly, those two stated above I found while doing research for this thread.
Some offerings can be made to appease the fae and to avoid any misfortune or mischief in the home. In Germany a jug of beer was left out for the cellar-dwelling kobolds; in Japan, rice wine appeased spirits and wandering souls who might do harm. It is always wise to leave water or food out to please the fae that linger in your home. In the morning the food will remain, but all the goodness and pleasant intentions put into this offering will be extracted.
Warding the Fae or appeasing the fae, either way it's a good idea to keep them happy, and keep them away. Once again they aren't love and light, glittery little things that make your wishes come true. Every time I think of this I think of the little faerie in Labyrinth, the one that bites Sarah...Hoggle gave some wise words...
Sarah: Ow! It bit me!
Hoggle: What'd you expect fairies to do?
Sarah: I thought they did nice things, like... like granting wishes.
Hoggle: Shows what *you* know, don't it?
Anyways, if anyone knows any other methods and would like to add their tid-bits feel free, always welcomed!
Adding a note here,
Some other methods are hanging a horse shoe above the entry doorway (Remember to keep it in the u shape to keep all the magic within. The only time you'll probably ever see a horse shoe hung upside down is at a black smith over the anvil, it is said that with the horse shoe upside down will pour magic over whatever the black smith creates on that anvil )
Another method is salt, now I don't do this, but putting small amount of salt in the four corners of the home wards off all sorts of Fae. (honestly, it just bugs my OCD and I don't do it cause I'll end up vacuuming it up the next day lol!) Like I said, there's a gazillion different ways to ward off the Fae, every culture has it's own method, and even those methods vary depending on the village and the people.
The Fae don't really have a reaction to iron and other metals...they just avoid it. They hate modern things, and iron is one of them as well as several other metals and objects.