Hogfather - Nail Clippings

'A special pot for nail clippings?' said the Verruca Gnome.

'Oh, can't be too careful,' said Ridcully, lifting the lid of an ornate jar marked BATH SALTS and pulling out a bottle of wine. 'Get hold of something like someone's nail clipping and you've got ' em under your control. That's real old magic. Dawn of time stuff.’

***

Hogfather - p110