Long ago, people used to treat frostbite by rubbing the affected area with snow. Now, of course, we know better than to do this. But even when I was a kid, it never made sense to me: “My toes are frozen, so I need to rub them with ice!” Does anyone know why this was the accepted treatment for frostbite? What was the reasoning behind it? I’ve searched the net, but only get links to sites that say, “Don’t do that!”
WAG: It did ease the pain of frostbite by further freezing the tissue and deadening the nerves sending the pain message. Short term relief at the cost of long term worse damage.
A related question is why some people once thought that you should treat burns with butter or fat? I tried that as a kid and it hurt even worse. Ice or cold water is both an intuitive and effective choice.
The Flynn effect states that IQ’s have been rising about three points a decade since the 1940’s. Extend that back far enough and you can see that most people just didn’t have the tools to deduce these things past a certain point.
I kid but I don’t. Urban legends today are bad enough. Imagine it with nurtionally challenged brains, inadequate science, and poor information flow through society.
It was a misguided attempt to slow the thawing.
** Frostbite Treatment ** 
Inquire of a search engine … 'Guess What? 
Time was, people didn’t necessarily have ice on hand all year round. But the butter was usually stored someplace that was at least cool. It may well have been the coldest thing available, so it sorta, kinda worked.