To prevent the occurrence of a dangerous chimney fire, chimneys should be given a thorough cleaning at least once a year or even every few weeks if you use your fireplace on a steady basis. The accumulation of creosote inside a chimney can build up to the point that this material will catch fire the next time you light your fireplace. There's no need to hire professional cleaners, as you can serve as your own chimney sweep if you are strong enough to do some strenuous physical labor and don't mind the possibility of getting dirty while doing it.
Invest in a good set of tools for chimney cleaning at your local home improvement store, including chimney brushes and rods, along with some form of eye protection, a tarp, an industrial vacuum cleaner, a heavy duty flashlight, dust masks and a jumpsuit unless you plan on wearing old clothes that you will launder or dispose of later.
Seal up the entrance to your fireplace using the tarp and some masking tape, and open the fireplace damper, the metal door located above the firebox. Now you're ready to climb up to the top of your roof with your rods and brushes, making sure to wear your eye goggles and dust mask for protection. Take the chimney cap off of the chimney and inspect it for any damages or weathering. This cap helps keep birds and other small animals out of the chimney, along with preventing sparks from flying out into the atmosphere and causing a fire.
Start to run your chimney brush up and down all sides of the chimney, making sure you brush down the dirt collected in the corners as well.
Replace the chimney cap and get safely back down off your roof and inside to the fireplace. Now use a short wire chimney brush to clean out the flue, the pipe that connects between the fireplace and the chimney. This is also a good time to inspect the flue and check to see if there are any holes that need repair.
There will probably be a pretty good accumulation of old ashes and creosote that has fallen down to the fireplace from your brushing efforts. Scoop up the majority of this with a dust pan and brush or vacuum up the debris with an industrial vacuum rather than your ruining your household vacuum. Continue to do a brushing of all sides of the fireplace, along with the smoke shelf in the cavity behind the fireplace, to remove old ashes and creosote buildup here.
Once you've vacuumed up all the debris knocked loose from your cleaning efforts, close the damper, and your fireplace and chimney are safe to use again.