As mentioned before in this series’ first post about creosote, there are three degrees, or stages, of creosote buildup. Chimney brushes are the standard method for removing first and second degree creosote.
However, sometimes second degree creosote will be hard enough to remove that other methods would work better:
- There are flat wire brushes which are pretty effective. They are expensive. If there’s a very thin coat of creosote on the chimney wall a flat wire brush will do a fair job of removing that too.
- There is special equipment for just this type of creosote. A rotary loop which is a stainless steel cable fixed to a hub that is put on special metal rods turned by a powerful drill (this process burns up regular drills) This method is quite effective.
- There are chemical creosote removers. They come in two kinds: the ones that take time and the ones that work fast. So said, “fast” still means a couple days. Fast chemicals definitely work, but they are not used much just because of the safety considerations and the expense of the return trip involved. They are very caustic and they can make a very big mess.
- Other chemicals, such as ACS or CreAway are effective over time, but are most useful as good maintenance. CreAway can actually reverse many problems given some time (weeks to months) provided one changes his burning habits. Continuing to burn the same way as you did to develop the problem in the first place has to stop if you want your chimney to clean up. (Consult your chimney sweep or the stove’s owner’s manual for best burning practices)
Third degree creosote removal is the most challenging of all. And sometimes it’s not worth removing the creosote- there’s often a very good case to be made for taking out the old chimney liner and putting in a new and different one. But first the removal options:
- The chemicals mentioned above can work if the creosote hasn’t been on fire. If the chimney walls just look like they have been coated with tar, the chemicals can work. The caustic chemicals, if used at all, are usually reserved for this type of problem.
- The flat wire brush and the rotary loop don’t stand a chance.
- If the creosote is hard there is a rotary head with chains that will do a rather effective job. Contrary to intuition, the chains will not break flue tiles. However, in chimneys that have been abused so that there is 3rd degree creosote the tiles are very often already broken. As a general statement it’s hard to find a sweep that will do rotary-chain-cleaning because he’ll get blamed for breaking the tiles. Even so, this is an option, and probably the most effective immediate-removal option.
- And sadly, you should probably have low expectations for how clean the chimney can ever be again. Once it’s been full of 3rd degree creosote, even specialized removal tools can get the chimney only so-clean.
In Part 3 we’ll discuss why it’s not a good idea to try to remove 3rd degree creosote from a tile chimney and then reuse it.