Above the back door of my house I have a horseshoe fixed to the wall. I knew that this was a good luck symbol but until very recently I had no idea that it was also a throwback to our ancestors' desire to protect their property against witches, ghosts, fairies and demons. Apertures such as windows and doors symbolised ways of entry and therefore the place where a house was vulnerable to bad spirits, so offerings would often be placed near doorways or under the front step.
Other impressive charms to ward off witches include the basket found behind the hearth of a house that contained a candlestick, a goblet, two shoes and various very dead chickens. Witches were also believed to attack a house via the hearth and chimney so witch bottles were often found in these places. We found a witch bottle in our 17th century cottage in Somerset. It was buried inside the inglenook fireplace and contained a dark sludgy liquid that was probably a mixture of urine and blood. Apparently witch bottles could also contain hair, nails and any other body part or fluid that you felt might help bring you individual protection against evil spirits!
Another superstition I came across when reading up about ways in which to ward off bad spirits was the idea of the "Witch wood." This was wood cut from the rowan tree and it could be nailed on the window sill or above the front door. It's interesting to me that we have a rowan by one gate into our garden and rosemary by the other gate. Rosemary, like the horseshoes, is a way of attracting positive forces and welcoming friends. So it seems we have a very nice combination of protection and positive energy. What is particularly interesting is that whilst the offence of Witchcraft was abolished in England in 1736, these old country traditions and susperstitions have survived. (Amendment: Thanks to Traxy's comment I have now checked my sources and see that The Witchcraft Act was brought in in 1736, not repealed, which makes a great deal more sense!)