I just went out and had a good look at the chimney, and just below the cap I see color change in the chimney pipe. It has the appearance of metal that has been heated. Almost like a rainbow effect to it. It only extends about a foot or so down from where it meets the cap. Is this normal?
![[Hearth.com] Changing color of class A chimney [Hearth.com] Changing color of class A chimney](https://www.hearth.com/talk/data/attachments/91/91553-76fdd7f9de27cef34fa9822b2c441ce8.jpg?hash=2UIdXssGM3)
