Caliper Rebuild - 3 pistons stuck

[speedyspaghetti]

Hey everyone,

I'm in in the process of doing a caliper rebuild, but I'm having a hard time with 3 of the brake pistons. I took out the dust boots, and then used the compressed air / wood method. One of the pistons shot right out, 1 budged a bit, an the other 2 did not move at all. Is there something I'm doing wrong, or do I have frozen pistons? I'm blowing the air through the hole where the caliper would connect to the brake line - is this correct? Or should I be blowing through the bleeder nipple? Any other suggestions? I have tried prying / pulling on them since I do not want to damage them.

Thanks!