If you want to do the characters white; nip down to halfords go to the trade/paint desk and they will sell you an empty touch up paint pen for a couple of quid. It has a fine rollerball nib. Spray some white paint into here, it should be easy do the characters with this as theyre recessed. Make sure you update the thread when you've done the caps, when theyre done this colour they really stand out against the white wheels