Originally Posted by Ascension
George, welcome to the forum. I look forward to discussing some detailing techniques for my Jet Black 330i. From what others have said, it's hard to keep this color fresh and clean
Thank you for the positive feedback Ascension. Best thing for black vehicles is to research and invest in the proper washing and drying tools, products and techniques. This will help minimize adding imperfections and creating more work for you in the future.
Hrm read through the entire post. If it were my vehicle, this would be the course of action I'd take. First I'd try cleaning with isopropyl alcohol and water mixture, if that failed, I'd give it a once over with a distilled vinegar and Water Mixture. Next I'd try claying the paint... followed by a chemical polish like Klasse AIO as picus mentioned. That fails, the next logical approach is to start with a light abrasive polish and move to a more aggressive polish until desired results are achieved. I have seen bird droppings quickly etch through the clear coat and need even more drastic measures taken, like wet sanding, but lets hope it doesn't escalate to that.
For the glass, can you feel the stain to the touch? What have you tried on the glass? You could try a razor blade + some water or quick detailer as lube to see if it budges the stain and if not you know it chemically stained the glass and if that's the case, it is not looking too good for your paint either.
Keep us posted on how you make out, if there is anything else I can try to help answer, please do not hesitate to ask.