There are occasions when a bathtub drain cover needs to be removed such as when the drain needs to be snaked. With water and mineral deposits the screw holding the cover onto the drain may have become rusted and stripped. Removing a stripped screw from the tub drain takes some diligence and the right tools. But the screw can usually be removed and a new stainless steel one can be put in its place.
Soak the screw in a lubricant like PB blaster. Make sure to spray the lubricant on as much of the screw as possible. Let it soak for a half an hour.
Use a screwdriver to remove the screw. Sometimes the lubricant will loosen the screw enough for it to be removed.
Use an electric drill with a steel drill bit to drill through the center of the screw. The drill bit should be the approximate size of the diameter of the screw. The bit will break apart the screw and the cover will be able to be removed.
Replace the screw with a stainless steel screw which will be less likely to rust and cause a problem in the future.