took the wheel off and gave it a good clean with p21s wheel cleaner, then made sure the bits i were going to paint were 100% dry by using a hair dryer. Then used very fine emery cloth to sand down the bits i was going to paint. Once that was done i just applied the paint with a very fine paintbrush, taking time to ensure i was doing the job right.
Some pics of before and after. You can tell from them its not a professional job but when on the car you cant really tell unless your up close, plus saved me £50 a wheel