So I've just picked up a relatively gently-used, white-painted carbon road bike for what I consider to have been a steal, and now I'm in the process of adjusting it to my requirements. One of those requirements is that the frame be spotless, because that's an important aspect of performance and usability that makes perfect sense to obsess over... Anyway, the previous owner had Jerry-rigged their compy and sensors onto the frame with an unholy alliance of zipties and electrical tape; and just as you'd expect, all manner of grime accumulated underneath those bits. Soapy water and the amount of elbow grease my spindly cyclist arms are able to manifest proved insufficient to remove many of the oilier patches, so my lovely white frame still has lots of grey-black blemishes which must be obliterated. What kind of gentle solvent/de-greaser/magic paste can I use to lift these stains without damaging the paint work or the frame?