88 Chevy Truck spark plug rusted, blown, threaded part stuck

Hi

My plow truck blew out the spark plug where it had coroded at the top of the threaded section. The small threaded stub remains in the block but all the rest was blown out.

I guess these plugs haven't been changed in years.

Any ideas how to remove the small stub. Also I'd like to change all the plugs but I'm afraid the plug will shear off leaving the stub remaining in the other cylinders.

Thanks in advance

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