There is a glass cover on top of the sensor, quite hard to remove. Extreme caution needed as there are tiny wires on two opposing sides of the sensor (shorter sides) - touching them gently is enough to break the sensor.
I managed to get it off by shattering some glass on the edge without wires and using a needle as a leverage, putting it into the hole, below the glass with caution not to touch the sensor.
I tried removing color filters and microlenses with flat screwdriver, a needle and a wooden toothpick. I don't recommend using sharp/rough tools made of hard materials - effects can be seen on this video.
I probably should use some chemicals to soften color filters layer, could be easier to remove.
