From what I understand, we need to open up the mouse and clean the scroll. But the biggest issue is opening it up. Its super hard. There are 3 clips in the battery compartment. I have bleeding fingers trying to open it. No success. Maybe I need to buy an iFixit kit.
See these videos :
https://www.youtube.com/watch?v=Kem0TE3UZyE&t=308s
https://www.youtube.com/watch?v=cVKXUiXl5ZY