The window in this property has been fitted with steel screws, all of which have rusted as the window is often open and inevitably moisture has reached the screw heads. My goal is to replace them all before the heads are corroded so much they cannot be removed in future. All the flat-head screws have been successfully replaced, but to the right of the frame you can see a single T30 torx screw head which is significantly corroded.
A. Remove the T30 screw and simply screw in a corrosion resistant equivalent of the same dimensions?
B. Leave the screw where it is, but treat the screw head to prevent further corrosion?
My hesitation relates to what exactly the torx screw is screwed into, as I suspect some of these fixings come with a plug assembly that the screw may be screwed into and I don't want to remove the screw and find I cannot drive a new one in. A rusted screw head (with corrosion resisting compound on it) is probably better than no screw at all!