Historically, attempts to answer the question have been made using various arguments, for example, by explaining away evil or reconciling evil with good.
Sharp steel - a needle - can turn away evil.
Amid celebration, garlic is used in different ways (according to local tradition) to banish and keep away evil spirits.
Suijigai are made from spider conchs and hung to ward away evil.
Gen is twisted grass hung from the corner of a house to ward away evil.
Salt is often placed at corners and in doorways to ward away evil.
When only the embers remain, young people leap across them to drive away evil and bring luck.
We use evil to fight and sweep away evil!
They evoked the power of the supernaturals to cure illness, drive away evil and bring good fortune.
Japanese ship launchings incorporate silver axes which are thought to bring good luck and scare away evil.