[header] How to clean chimneys [title] Determine whether the chimney needs to be cleaned. [step] Chimneys should be cleaned at least once a year, and more often if you use your fireplace frequently. [substeps] Take a flashlight and peer inside the chimney flute. 
Use a pencil or plastic knife to scrape off a bit of the creosote that has accumulated on the side of the chimney. If it's 1/8-inch thick or thicker, it's time for a cleaning.