is this rear caliper salvageable?

[Bretty]

Well I couldn't push the pistons out, as there is now air in the brake line. I probably should have bled it and persevered, but instead have split the caliper.
The outer seals look knackered for sure, and pistons are pretty corroded on the inside. I have no idea how to get the pistons out now, but for the cost of new pistons and seals I might as well hunt for a half decent secondhand caliper....