@onnjeyyon,
i also discovered that when my friend go play my fan. he simply turn it, see see got light

last time i just wash my fans under running water. then leave them to dry for few days to nearly a week before i use them again.

btw, that's a whole lot of dust inside your casing.

yeah too dusty, imagine nearly 1 1/2 years without any cleaning
and i dont have a vacuum with me at that time, so just wash like that. made sure everything is really dry before i put it back in my case again