The tools and methods used to clean a masonry fireplace chimney depend on the height of the chimney, the type of chimney liner that it has, and your access to the roof.
Usually it is done with fiberglass rods and wire brushes.
Sometimes it can be done from below. Wood fireplaces tend to burn quite cleanly and just have a bit of clean smelling ash on the walls instead of the tar that builds up with the stove.
To clean it from below, you can start out with a 4-in round wire brush, then switch out to a 5-in round wire brush, and then go up in size to a 6 in round wire brush
This is assuming that you have a 7-in square terra cotta chimney liner…
Get a piece of pink fiberglass insulation and hold it up against the damper slot once you have inserted the brush into the bottom of the fireplace chimney and push it up, scrubbing back and forth, as you work your way up the chimney.
The pink insulation will catch the ashes that fall down to try to minimize the amount of ashes falling on your hands and head while you’re working.
Dump the ashes into a bucket and clean up with a whisk broom and dust pan then use a shop vac to clean up the rest of the ashes.
If you’re dealing with tar, and the chimney is plugged shut then you very likely will have to work from the top and that involves things like digging irons and chains….
Lime powder squirted into the chimney draft with a special dispensing cardboard tube like baby powder breaks down tar
and turns it into a dry cornpuff like substance that is much easier to remove.
This is more of a maintenance item, as you must do that while you still have some draft in your chimney.