after it was washed

This can be translated in active form. AT: "after the owner washed it" (See: rc://en/ta/man/translate/figs-activepassive)

You must burn

Here "you" does not refer to the priest specifically. It just means someone must burn the item.

This can be translated in active form. AT: "if the owner washes it" (See: rc://en/ta/man/translate/figs-activepassive)

This can be translated in active form. AT: "then the owner must wash it" (See: rc://en/ta/man/translate/figs-activepassive)

Something that God has declared to be fit for people to touch is spoken of as if it were physically clean. (See: rc://en/ta/man/translate/figs-metaphor)