The weird point about these three fans (two of the same type and one of another type) is that there are no screwdrives, meaning I can't see a way to "open" them.
It looks like there's an arrow on the black plastic, maybe for telling that this way it can be removed.
I just need to take the upper part off, not all the fan out of the graphic chip.
The model numbers of the fans are (nothing on the net I could find about these, apart from specs...)
B0535AEB2-8 (two of these on the card)
B0502AFB2-8 (one on these on the card)
I hope there's a way to clean them with properly...
Little one:
Bigger ones:
Hope you'll be able to help me out...