Hmmm... The old wives tale, about putting butter on cat's feet. Seems there's some truth, in that. I believe the key down the back made you put your head back, or something. It seems to have come to this country, from Europe, a long time ago. Apparently, if I remember rightly, the keys (or anything cold enough, like an ice-cube) work because of the mammalian "dive reflex". Cold hits the nerves in the neck, causing the blood vessels to constrict. You might notice your pulse slowing too. The dive reflex is why cold-water drowning victims are not usually pronounced dead, until they're "warm and dead", as it were. Cold water in the face/head area shunts blood to the organs and away from the skin, which slows the metabolism for survival. The vital signs are often too weak to detect, otherwise.
I think there're many variations of the doorstep thing. Chinkoff was Jane's nan's. My mother used to say that it'd give you double-pneumonia (Lack of imagination, methinks).
If you pulled a face, she said that "one day, your face will stay like that". Dunno what her excuse is...

I can imagine Lissy using that one, for some reason.

I love the variations of the "Standing here like a tit in a trance" thing. Around Manchester, they say "Standing around like Piffy on a rock bun", yet nobody knows who the heck Piffy is, or was, nor how the saying might've originated.