So, I got excited, and didn't anticipate well how profound the knot would sit in the handle. The knot is glued in with silicone (maybe a little bit too much), and I would like to rescue both knot and handle without damage.
The general advice is: You can just pull it, but Nature has gifted me with the grip strength of a 5 year old child. I have tried it. It simply doesn't move. Since there are a few chemically and physically knowledgeable people here, my question is: how do I get the knot out, when (my) brute force just does not cut it?
https://m.youtube.com/watch?v=9q0T7MhfN6k solution at about minute 3
Silicone becomes a bit more brittle at high temperatures so that is one option, otherwise you could try putting the brush in the freezer overnight so that the silicone becomes more brittle while cold.
Mind that I know nothing about knots and handles, so I don't know what could ruin them