Rejex is a military grade product developed to use on airplane fuselages (painted or not) and does not leave a trace on plastic or rubber when applied correctly. It is particularly good at eliminating the attachment of carbon/exhaust residues and is available commercially as Rejex. I say this because I have tried and used both on automobiles, and it works about the same as RainX on glass. Works real well (like RainX) initially, but has to be reapplied regularly to maintain effectiveness. It also requires buffing out and behaves much like RainX where in certain conditions there seems to be a film. I have used a water soaked cloth after applying both and polishing with water and then a dry cloth, barely a perceptible difference that I could make out. Now the new ceramic coatings are claiming effectiveness on glass, but I have not tried them to date. They might be the answer?