At the moment, it's perfectly possible for a cleric or someone with GoD to come into a temple area and desecrate four to five altars in a matter of minutes, but fixing their work takes far longer since it requires finding (or in most cases, creating) a cleric of the appropriate god or taking a currently-existing cleric, having them change gods, pay 12k (or irl hours) of praying to get their piety up before reconsecrating the altar. Cleric is not nearly as popular a class as it once was, so finding a cleric at all can be a struggle in and of itself.
I propose a "cleansing" ritual that could be performed by any cleric or favored soul, which would take more effort than desecration but would provide an alternative to rolling up a cleric you'll delete within minutes or having existing clerics swap their gods in order to reconsecrate the altars. This ritual, if successful, would simply undo the desecration, leaving the altar consecrated to whatever god the altar was originally dedicated to.