The ritualistic throwing of coins into so-called 'wishing wells' has pagan animistic origins rooted in material vitalism. Celtic and Germanic peoples believed that water was sacred, having been placed there by, and containing deities.
When crossing rivers, or following battles on nearby plains, coins and armour would be thrown into the water as offerings to such virtual beings which resided within the physical landscape. Water was also seen to have healing powers and therefore wells became popular with many people drinking, bathing or just simply wishing over it. People believe that the guardians or dwellers of the well would grant them their wish if they paid a price. After uttering the wish, one would generally drop coins in the well. That wish would then be granted by the guardian or dweller, based upon how the coin would land at the bottom of the well.
The material world was thus brought into contact with the virtual through ritual.
Perhaps unbeknown to the protagonists of the ritual, the copper and silver of which coins were made also had biocidal properties which kept the water from going sour (bacteria produces various acidic compounds which affect the taste, notably Hydrogen sulfide). As well as expressing the merging of a virtual and actual world, the ritual also serves as an example of material vitalism; with inorganic matter dramatically altering both its immediate environment and those who rely upon it.