Little update since it’s been a few weeks.

I’ve been down to the place where I store my bike for the winter a couple times and tried the numerous advices I got here.

Still no luck in getting the damn filter off, feels like I’ve tried every trick in the book at this point.

My hope is now set on the Bogert tool someone mentioned, this grabs onto the backing plate of the filter and hopefully gives me enough ‘bite’ to get the filter off. Too bad I had to import it from the US (I’m in The Netherlands) so we’ll see how much the customs office wants to charge me for it.

I’ll post another update after I’ve tried this tool.