In my bathroom, my current project, there is an old cast iron ventilation grille in the wall. It currently has a cheap white plastic grille cover on it.
I'm going to be wanting to remove the cast iron grille and as per my sparky's advice, replace with a sheet of wood, screwed to the wall flush, of which a 100mm hole will be cut in the centre and an electric extractor fan fixed to it.
So, how would I go about removing the iron grille? the house was buit in the 1920's, so screws are unlikely to be holding it in.