Measure the inside diameter of the chimney flue with a tape measure. This will determine the size of the chimney brush. Purchase the flue brush from your local do-it-yourself retailer.
Cover the floor in front of the fireplace or wood stove with painter's plastic. Cut the plastic to length with a utility knife and secure the plastic with duct tape. Hold one end of the plastic 12 to 24 inches above the front of the fireplace and tape the end of the plastic sheet to the fireplace surround to create a protected work area. This will keep loose soot from entering your home.
Put on a protective suit, respirator and safety glasses.
Assemble the chimney brush per the manufacturer's assembly instructions. Make sure to tighten each connection of the chimney brush push rod.
Slide the end of the assembled chimney brush into the chimney flue. Push the chimney brush up until you reach the top of the flue.
Pull the chimney brush toward you. Take caution as loose soot will fall onto you and your protective plastic barrier. Alternate pushing and pulling the chimney brush through the chimney flue until no soot remains on the walls of the flue.
Remove the soot from the painters plastic and the inside of the fireplace or woodstove with a wet/dry vacuum. Make sure the vacuum filter is in place and clean before operating the vacuum.
Dispose of the protective paper suit and painter's plastic after cleanup is complete.