Please choose the correct ending to complete the given sentence: Home and Garden: [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.

Ending1: If the mouthpiece is intact, there should be no soot buildup or broken parts inside. If the vacuum nozzle is missing, you will have to replace it more frequently. Ending2: If you can see the exterior glass of the flute, the chimney needs to be cleaned more frequently than if it's dry. If the exterior glass is cracked, replace the inside glass until the glass is completely white. Ending3: 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. Ending4: The flute is circular and connects the glass panes using small brass inner ports. Simple deflation is often the problem, but larger chimney pieces may need repairs more often.

Answer format: ending1/ending2/ending3/ending4