If the soot has a matte black finish and the scratch is 1/8 in. deep or less, its a DIY job. But if the buildup is deeper or has a shiny, tar-like appearance, you have heavy creosote buildup.

By Karen Youso, Star Tribune, Minneapolis Jan 12, 2008 Jan 12, 2008Updated Apr 22, 2014 0 ...

The firebox itself can be a point of concern and contribute to failure, so Campbell’s experts examine the firebox and fireplace for gaps and cracks, excessive soot, and missing or broken bricks.