Salt and Iron is one of three methods for demising a witch.
Alongside a Spook's trusty rowan staff and his valuable silver chain, salt and iron is another weapon a Spook will always carry with him.
One in each pocket, this lethal combination will surely kill a witch; no matter what.
Use by Spooks
Spooks use the exploit of salt and iron to their advantage.
They buy bags of salt in bulk; always having a bag at hand for anything that should come up. As for their iron, they buy this from blacksmiths, or, as John Gregory refers to them 'smithies'.
At his Windmill, Bill Arkwright used a mixture of salt and iron, inserting it into his moat. This kept any witches out of his Windmill confines, keeping him and his belongings safe, whilst also keeping unwanted visitors out.
- This is the most common way of dealing with a witch.