Unfortunately, I am not aware that you can remove the knife from the container. Creativity is needed here;-)

There is a special tool for this. But honestly, I wouldn't "tinker" with it myself. You have a 10-year guarantee... even if this is probably not covered by the guarantee... but the thing is simply too expensive. I recommend you to contact the company Keimling... I don't know if I'm allowed to write this and maybe my answer won't be published. They have already helped me and I was more than satisfied with their service. Maybe if you fill the container with water and let it sit for a few days, the fibres will dissolve/soften.