Any remedies on how to cure stuck caliper pistons?

1. Compressed air in the brake line opening. Put a piece of wood or something else soft to catch the piston as it comes out of the bore so not to mar the piston surfaces

   or my favorite

2. Screw a zerk fitting into the caliper (or wheel cylinder) brake line opening and use a lever arm grease gun to gently force the piston out.

If you use a grease gun, clean the caliper or wheel cylinder completely before re-assembly. I soak them in carb cleaner overnight, rinse, blow out with compressed air, do a final rinse with brake cleaner, then blow out with compressed air again. Always replace the o-rings & seals if you do this.