Disclaimer
Removing the brakes from your vehicle can be dangerous. Please DO NOT do this mod if you don't know what you're doing or are uncomfortable with removing your brakes.
Tools & Materials
Caliper Spray Paint
Large Plastic Sheet (painting dropcloth)
Scissors
Wire Brush (and/or Green Scrubbie pad)
Brake Parts Cleaner
Masking Tape
Ratchet with sockets(mine were 14mm & 17mm but your sizes may differ)
Torque wrench
Jack, Jack Stands, wheel chock
Milk crate (or small trash can or plant pot)
The Project:
1. Jack the end of the car (front or rear) that you're wanting to paint the calipers on and remove the wheels.
2. Loosen and remove the caliper slider bolts and the caliper mounting bracket bolts.
3. Remove the caliper and the bracket and set them on a milk crate (or equivalent) positioned next to the rotor. [NOTE: for rear discs, there is a bracket holding the line that makes it difficult to get the caliper away from the car enough to place it on the crate. You can use a pair of pliers to remove the clip holding the line and thus get lots of extra room.]
4. Remove the brake pads, metal plates, and caliper slider boots and set them aside.
5. Using the brake parts cleaner, wire brush and/or green scrubby pad, clean the brakes thoroughly.
6. Cut a slit in the bottom of the plastic sheet and poke the caliper through it with the brake line being the only thing in the slit. Fold the halves made by the slit over each other so that the caliper is the only thing on the outside of the plastic sheet and the rest of the car is covered.
7. Cover the brake piston(& boot), bleeder valve, and all threaded holes with masking tape.
8. Begin painting according to spray can instructions. While you are waiting for coats to dry, clean the metal pads you removed from the caliper.

9. When you're done painting the first caliper, repeat steps 2-8 on the other caliper.
10. Once everything is dry, remove tape, reassemble and re-torque the bolts.
11. If you have decals, now is the time to put them on.
12. Put the wheels back on, lower the car, re-torque lug nuts.