Spark plug wire holders

Need advice. Is there a trick or easy way to remove remnants of broke spark plug wire holder stud from the cam covers? Thanks. Charlie

 

The hole in the valve cover is threaded. If any is sticking out grab it and spin it out.
If not, drill a small hole in the center and stick a small sheet metal screw in there and pull out the center pin then use a small screw driver to grab the outer shell and spin it out.

 

Thank you.

 

For reference the thread pitch is m7x1. The plastic inserts use a center push in to expand the outer sleeve into the threads.

 

Perfect. Worked like a charm. Thanks again.