An old wives' tale that persists today is that conkers are not only suitable for battle, but will keep spiders out of a house. For maximum effect, it is said that the conkers should be spread around near doors and windows.
Such is the spiders' dread of conkers, it is said, that not only will spiders not enter a house guarded in this way, but spiders already living under the roof will flee in terror.
We have no data to prove or disprove this assertion, but we have overheard it in the office as recently as today.
In some ways, this contains a whiff of other folkloric motifs. Spiders are traditionally associated with evil and most evil presences are said to be deterred from entering a person's home by the distribution of a specific amulet. Most famously garlic is said to keep vampires from one's door, while witch bottles are still periodically unearthed under the threshold of old houses.