Once the flail head has been used to clear most of any debris or ash build up, it can be replaced with the bristle head for final cleaning if necessary. The bristle head is connected to the rods using an identical coupling system as the rods themselves as shown in the illustrations. It does not require rotation and is simply pushed using the hand grip. It can be used with as many rods as are necessary to brush the entire vertical flue or, normally, just with one rod to clean the horizontal section of flue connected to the incinerator toilet.
When maintenance requires the horizontal flue to be cleaned, it is normal practice to disconnect the incinerator toilet and move it away from the flue and combustion air pipes. Given such access, the bristle head can be used to clean the flue.