Spanner, I usually use a long sharp pick tool, forced into one of the holes. Get the thing to turn in the groove first, then lever it up, bending it, and finally getting it up far ehough in the bore to the point where a stout pair of needle nose will grip it. Then just kind of "wind" or twist and pull up carefully. I never bought the pliers. It sounds like a nasty way to do it, but done carefully, it works good. You might want to spray some good penatrating oil like PB blaster in there to eat some of the corrosion, and let it soak a while before you start. Seems like I've used both a long straight pick and a long 90 degree ended one alternately. Having only one hole left to work with is a bummer. Patience, as I'm sure you know, goes a long way. Hope you get it out w/o too much damage/frustration.