1) Remove the caliper from the bike.
2) Remove the brake pads.
3) Use a C-clamp to compress the piston into the caliper.
4) Once the piston is compressed as far as it will go, use a flathead screwdriver to pry it out of the caliper.
5) Repeat steps 3-4 for all of the pistons in the caliper.
6) Clean the calipers and pistons with brake cleaner.
7) Reinstall the pistons in the reverse order that they were removed.
8) Reinstall the brake pads and caliper.
9) Bleed the brakes.
