Wood-burning fireplaces and chimneys should be inspected annually, or after about 80 fires, by a certified chimney sweep. The home must have functioning carbon-monoxide detectors. This is not negotiable — any fireplace or chimney that's not functioning perfectly can kill your family, either through fire or noxious fumes.
Common problems are malfunctioning flues, damaged chimney liners and blockages from nesting critters. A chimney cap and a spark arrester can reduce risks. Your chimney sweep company should be certified by the Chimney Safety Institute of America or the National Chimney Sweep Guild.
Before making a fire in a traditional fireplace, open the damper and crack open a window. Light a match, blow it out and watch the smoke to see whether it's properly going up the chimney. Think twice about using the fireplace on gusty days, when opening a door can change room pressure enough to coat furniture with a flurry of ash. Place a nonflammable rug (available at fireplace-supply stores) in front of the fireplace so that sparks won't damage your flooring. Don't burn a fire for longer than five hours.
To clean stains on glass doors: When the fireplace is cool, scrape off door deposits with a razor blade. Add liquid dishwashing detergent to a bucket of warm water, or a cup of vinegar to a gallon of water. Spray or sponge the cleaner on, then wipe away with newspaper. Or try glass cleaner from a fireplace store. Shine brass fireplace utensils with Worcestershire sauce and a toothbrush.
To clean ashes: Fireplace coals can remain hot enough to start a fire up to three days, so wait at least that long before removing ashes. Then, open the damper and crack a window so that ash isn't drawn into the house. Wear a dust mask and shovel ashes into a metal container; store it far from combustibles and wood floors. (Vacuuming ashes can leave you with a bigger mess.) During fireplace season, leave about an inch of ash at the bottom of the fireplace to act as insulation for your next fire.