Well, I tried Goo Gone both when the pipe was cold and when it was bit warm. I also left it on for few mins. Looks bit lighter but still visible.
This is a response from Vance Hines tech: "Unfortunately there is nothing available. Our ceramic coated product holds up very well to heat but not to harsh cleaning chemicals. We do not recommend to clean our black ceramic product with nothing else other than warm soapy water."
I think the wise thing to do is to try to stay away from the pipe which is kind of hard to do on a fatboy with a half-moon footboard close to it. Better yet, install a heatshield.