I did a write up on this topic in my AluFelgen CSL wheel review. It's probably buried, but like everyone is saying, just clean and green scotch brite pad the hat part and paint with high temp engine or header paint. I used a "cast iron" colored 500 degree header paint that just looks awesome!
"The likelihood of one individual being right increases in direct proportion to the intensity with which others attempt to prove him wrong."
'12 335is MWM / Coral Red / DCT / Nav / Cold / Premium / Convenience / H-K / JBSPEED M3 lip / COBB AP V3 / ER CP / HKS BOV / BMS DCI / Scoops / Mishimoto FMIC