eroded antenna cap(the silver piece)

this happen to anybody? the top of the cap if eroded away; nothing to put a screw driver up to… what am i gonna do?

If you can get a new cap,you could try a dremel tool to score the old one enough to get the proper tool to get something to dig into or do what I did.I got my buddy a screwdriver and hammer put the screwdriver one on each side of the cap and tap away counterclockwise until unscrews.