I am in the process of replacing the deck screws on my composite deck, which are corroding even though they were guaranteed not to. My problem is that because they have corroded some break off below the joist surface. Working the screw gently back and forth doesn't always work because it is corroded fast to the joist. Also, I have noticed that the break point is severely corroded and very weak. I have tried various things to remove them. Because the broken piece is below the surface I can’t get a hold of it with vice grips. I tried a product call “The Extractor” which is a tubular type bit that bores around the outside of the screw. I have had limited success with this product. The screws are very hard and drilling out the broken part is not possible. I have resorted to hammering the broken piece further into the joist, drilling a hole and gluing in a plug. Because of the corrosion the broken screw is securely attached to the joist and hammering in is also difficult. Does anyone have any thoughts: (1) to remove the screws without breaking; (2) removing the broken screw; (3) is hammering in the broken piece a good option; (4) how to preserve the dowels I am using as plugs; (5) any other options for plugs. Thanks for your input.