Examples:

• Don't worry. I'm clean as a whistle.
• Guy is clean as a whistle.
• I'm clean as a whistle now and always.
• And you, my friend, are clean as a whistle.
• Yeah, no, heart's clean as a whistle.
• Because he's a she, and I am clean as a whistle.
• I'm clean as a whistle, you understand me?
• And asbestos reasons, but it's clean as a whistle now.
• His shoes are clean as a whistle.
• The guy's clean as a whistle.