Raggytash, although my mother's warning was sound, the reason she gave was completely wrong.

As for chilblains, I believe it is to do with the circulation, which is why stamping might help. We used to get chilblains on our feet when we had to stand in the cold and wet, waiting for the bus to school.
An old woman who lived in a crumbling cottage in the woods told us that we should treat chilblains with wall penny-wort. We dutifully collected the plant and rubbed our toes with it. The effect was probably achieved by the massage involved in rubbing our toes with the plant, more than by the plant extracts themselves.