The author uses a question to state that the sacrifices were limited in their power. This can be stated in active form. Alternate translation: "they would have ceased offering those sacrifices." (See: [[rc://en/ta/man/translate/figs-rquestion]] and [[rc://en/ta/man/translate/figs-activepassive]])
Here being cleansed represents no longer being guilty of sin. This can be stated in active form. Alternate translation: "the sacrifices would have taken away the worshipers' sin once, and they would" or "God would have made the worshipers no longer guilty of sin once, and they would" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-activepassive]])