Clean as a whistle
(... rất sạch sẽ / lý lịch rất trong sạch)
Meaning: If something is as clean as a whistle, it's extremely clean, or for a person it can mean they have a perfect record and have never done anything illegal.
- A political party will make sure a member's background is as clean as a whistle before letting them run for office.
- Everything in a hospital should be as clean as a whistle.