Freeze/core plug replacement

[Phil Bates <jello@ida.net>]

I had a leaking core plug.  I've since removed it, and have a 
replacement plug available for it.  What is the best way to expand these 
plugs.  This in in an MGA, and the engine is in the car - so I have 
limited space for swinging a hammer.  I've heard that I should use a 
socket to hit it, and one that is as close to the diameter of the hole 
as possible so that I don't deform the plug - does that sound right?/

Phil Bates