i had to hammer two of mine off, its more simple to just replace the old full fitting for one with a different brush on, or screw brush off and screw different one on,
i noticed the older one has a spring in and the newer ones dont, they could still do with remoddeling.
tools needed to change, posie screw driver / hammer.brute strengh.
sorry Alex but this is how i had to get mine off. i just remove whole brush setup from pole and change , easier and safet.