In my work in progress -- Under the Skin-- there's a scene with a 'witchy woman' back in 1887 healing a burn. I needed information on Appalachian folk medicine and Cavender's book is packed with it.
The book gives the following charm: "There came an angel from the east, bringing fire and frost. In frost, out fire. In the name of the Father, the Son, and the Holy Ghost."
I also checked with my friend Byron, a hereditary Appalachian witch, who gave me the charm she uses. Come three angels from the North, take both fire and frost.
I used Byron's shorter version in the scene I wrote. But what I found really interesting was this post from England clearly pointing to a pagan origin for the charm -- before it was 'sanitized' by the invocation of the Trinity. (You'll have to scroll through a bunch of interesting stuff about blackberries before you get to the charm.)
Three ladies came from the east. One with fire and two with frost. Out with fire, in with frost. The three ladies are said to be an invocation to Brigit, the Celtic goddess.
You can find these survivals in every culture -- where an older religion is supplanted by a newer -- but the deities of the old religion are transformed into devils or angels or saints -- there is a St. Brigit, isn't there?