Press it against a rigid, flat(tish) rubber surface, a mousemat or the wall of a car tyre work well. Put it flat agaisnt the rubber, push hard and rotate.
Cheers thanks for the help, got it off using the mouse matPress it against a rigid, flat(tish) rubber surface, a mousemat or the wall of a car tyre work well. Put it flat agaisnt the rubber, push hard and rotate.
In the future you could just use an elastic band around the filter for grip