諸經要集 20.108

20.108

又五百問事云。不得口吹經上塵。像塵准之。雖非正經然須慎之。亦不得燒故經。得重罪如燒父母。不知有罪者輕。

Furthermore, the Wubai wenshi states: One must not blow with one's mouth upon the dust on a scripture; dust on images is treated in the same way. Although they may not be the primary canonical scriptures, one must still be cautious with them. Nor may one burn old scriptures; this incurs a grave sin comparable to burning one's parents. For those who do not know it is a sin, it is lighter.