C1147 The Formation Can't Stop It

See here, maybe someone asked if the sewage in the sewers wasn't dirty? Why wasn't there a destructive spell?

It doesn't mean that all filthy things can destroy spells. Then isn't the dirt on your hands also filthy? Real filthy things were excrement and blood, while excrement and urine were differentiated. For example, not only is the urine of a child not dirty