[yorkie_chris]

Yes you use the brake system to push them out if they're stuck, or compressed air if they move OK anyway. (after removing pads etc.)

I use this method, yes you do get some brake fluid over you but don't whinge it won't kill you (much), then I detatch the caliper from hoses, remove the seals, scrape any corrosion out of the seal grooves, clean them up with dremel brush thing, clean the rest of the caliper like where the pads sit with a wire brush, then use brake cleaner to get the lot sparkly clean, especially the fluid passageways.

Then, I pack the seal grooves with red rubber grease, put the seals in and press them into the grooves and wipe out excess grease, keeping the amount in the cylinder itself to a minimum, wipe this excess over the sides of the piston and slide it back in. Copperslip the back of the pads, pad springs and retaining pin, rubber grease on the rubbers and put it all back together.