How to remove outside cover of extractor fan?

[adamt11]

Hi,
I would like to remove the outside cover to clean the inside. This is what it looks like.

Do you just remove the plastic covers with a tool and then use a screwdriver?

Thanks

 

[Burnerman]

Usually, yes....is that a blob of silicone covering one of the screw heads?
John

 

[foxhole]

Easier to clean from inside , External May have been silicones in.