There is a comment in Chemistry in Britain for February, by Paul Kelly, concerning the mysterious "witch bottles" employed two centuries ago to ward off the malevolence of local witches towards their neighbours. The bottles were made of glass or stoneware and were filled with a mixture of odd materials and buried somewhere in the fabric of a house. Traditionally, these charms were said to contain nails, pins, thorns and a liquid which might be urine or salt water.
Kelly writes that Alan Massey of Loughborough university is currently examining the contents of a witch bottle unearthed in Reigate recently. He has found nine brass pins coated with copper sulphide, with traces of phosphorus and carbonate, but no organic residue that would indicate urine. The sulphide may have been derived from gunpowder, often added to such mixtures, but no charcoal has been detected. Considerable doubt therefore remains concerning the exact nature of the materials originally placed in the bottle.