St. Euny’s Well (also known as St. Eurinus’s Well or St. Uny’s Well) is said to cure all sorts of ailments, “dries humours” and heals wounds. The waters work only on the last day of the year, and on the first three Wednesdays in May. Children that are to be treated should be “dipped and dragged widdershins [sic] through the water”. The curative waters of the well are said to be most effective on the first three mornings of May.
For further information, please read Haunted Britain by Antony D. Hippisley Coxe.