moonlite
Kona Fan
Nice one -- that's an improvement over my idea of two holes and pliers!Drill small pilot hole in centre of piston.
Find a HEFTY self tapping screw
Find a stout piece of material (metal, maybe wood with washers) and drill it so that the screw thread will pass through freely (but not the screw head)
place the screw through the material and butt that up against the caliper body
find spacers/stack washers so that the screw can screw a fair way into the piston but it can't pull into/through the metal/wood block
tighten the screw and it will pull the piston out.