I'm thinking to let the piston sit in the warm crockpot antifreeze overnight, then scrape inside the piston's wrist pin bore with a small hardwood scraper, likely a modified toothpick.  The bore likely has castor oil baked onto it.  I could use a drill bit to get at it, but do not want to scratch the bearing surface.

Great ideas.  What solvent on the Q-Tip?  I guess I can use green antifreeze.

Pays to warm it, to pull the pads. then there flexable & the ends dont snap .

A toothpick or 1/16 wire through the pin , and polish it , on 12000 paper on a flat surface , maybe .

Forceps catapult pins into the beyond. beware .

Holding the pin , rotate the piston . Shouldnt necesarilly be entirely ' free ' , as if youve held a new floating gudeon - piston , and rotated , youll of felt .

Though it should be nearly free . Oil the sucker'n it will be. Maybe Singer oil . No Binding .