A diaper pail packed with a used liner still inside is the single most common odor mistake in a baby gear move, so cleaning it out comes before anything else.
Pro tip: A short soak in a diluted vinegar solution before the final rinse neutralizes lingering odor better than soap alone.
Watch out: Never pack a diaper pail with a used liner or cartridge still inside, even sealed, it is a strong odor and hygiene risk over the course of a move.