I wonder if you could saw off the end then drill to get a solid surface on which to use a punch. Just a thought.....
Yeah i searched on the forum and someone did that, didn't work. But i think i'm going to cuz off the ends like you said, and then just drill out the remaining pieces and smooth the hole out. Caliper albeit rusty on the outside, the pistons are still nice and shiny under the dust boot. It's salvageable