I had a buddy years ago who had an Opel Manta with sticky calipers. He was a competent mechanic but short on time and money so about once a year he and I would use a big C-clamp and "catch" the puck so it didn't pop out of the bore. We'd work it in and out a few times and all would be good for year or so. Nowadays you can get rebuilt calipers cheaply enough that it might not be worth messing with this technique - but you COULD.

Dan