Harry hauled one of his baby teeth out last night. It was on the way, but he decided it should be hurried along. He stashed it, wrapped in a bloody tissue, under his pillow, as you do. Come time for me to don my fairy wings and swap it for a quid, confounded by lack of specie. Or of specific specie anyway. I don't think he'd have been in impressed by a pile of 2ps spilling out from under his pillow. Franticly ransacking the house at midnight, finally found one lurking at the back of the keys-and-that-kind-of-thing drawer in the kitchen, but came damn close to stealing one from Harry's own moneybox.
I only know the word specie because I've been reading Neal Stephenson. And yes, I would have replaced it pretty sharpish because he'd be guaranteed to notice if I hadn't. Finally, swapping a tooth for a pound always provokes wild stories about friends of friends, or in other classes at school, who get five or even ten pounds per tooth. I smile indulgently and say "oh, really".