Substances like Brakekleen and Berryman's will take grease, etc. off in a hurry, but they can be brutal on rubber hoses and seals. I would stay away from them on assembled calipers. I hit the suckers with Simple Green Automotive and buzzed them with steel wool. When I rinsed, I paid special attention to ensure that no little metal strands were left over from the steel wool. In the hot sun, the brakes dried in a hurry, and were ready for paint. Since my beast is Tropic Green, I painted the calipers yellow and the brackets black. Everything was handpainted, and came out all the better for it. Yellow took 7 coats to cover, black took 3. Red should be quite a bit more user friendly than yellow.