Removing trickle vent in 1980s wooden casement window

[Erichsonb]

Hello,

I'm in the process of refurbishing my 1980s wooden casement windows. I'd like to remove the trickle vents to clean them (see pic attached). Has anyone seen vents like this before and do you know if they cab be easily removed, cleaned and reinstalled?

Would be so grateful for any replies.

Thanks

 

[crank39]

Can't really tell from those pictures but they could be set on top of the glass in which case they're staying put unless you declare the window