From Ardrana

The clean spell enables the caster to remove heavy soil, dirt and like foreign objects from floors, walls, dishes, windows, etc. These surfaces are then spotless. Usually only one type of material is treated in a single application, as care must be taken in removal of pigments and the like.

The reverse of this spell, dirty, enables the caster to soil, spot, and sully walls, floors, dishes, garments, and so on.

Note: This spell originally appeared in this form in Unearthed Arcana for Advanced Dungeons & Dragons from TSR. Its use here is for the purposes of providing context for the campaign only.