No offence to Nick, but if you have an AutoSmart franchisor close to you, try them. I'm sure they have a cleanser/polish specifically for black paintwork on motors.
As you now know, black is a real pig to keep clean and looking good, which is why they have this product - or did years ago when I bought it from them for personal use.
As to the dead beasties - why not soak them by laying a wet soapy cloth over them while you're doing another part of the job? They should be softened up after a while.
Best of luck whatever you go for.