Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to use a fireplace safely [title] Burn safe materials. [step] Only burn natural materials in your fireplace; never introduce foreign substances, including cardboard, newspaper, or paper trash. These substances burn poorly, produce a lot of smoke, and release chemicals into the air.

Ending1: Therefore, if you suspect that something combustible might be in your fireplace, remove it and store it in a safe place. [substeps] Do not allow pets or children to enter your home while watching a fire; even unexpected small children can cause problems with burns. Ending2: Make sure to ensure that any fireplace/wood you're using is equipped with fire extinguishers. [substeps] Always contact the professionals or fire extinguisher experts if you are not sure where to get a fire extinguisher at this point. Ending3: Only burn tinder (such as pine needles or tiny sticks), kindling (small sticks or pinecones), and fuel (large logs, up to about 14 " long). [substeps] Burning hardwood (such as maple and oak) will diminish the amount of soot and ash buildup in your chimney. Ending4: [substeps] Use candles and incense to keep yourself safe. You can light incense infrequently.

Answer format: ending1/ending2/ending3/ending4