Wipe down after most rides with warm water/damp rag, occasionally wash with dish soap and water followed by Nu finish wax. Never saw the need for any special carbon cleaner if it's been sealed with a clear coat.
__________________ Feel the Burn? That's the sickness and the cure!
I've never had the need to clean my headset spacers.
Have you had any issues with your carbon spacers? I had a friend with a problem keeping his headset tight. Turns out the carbon spacers weren't cut right. That's one reason I use the ridiculously priced CK spacers. Perfectly faced every time. Plus the cool colors.