I keep a small old towel in my garage, squirt WD-40 on it and clean the tips, every time I park in my garage. They look like new. I may wax once a year.
Fine steel wool.
I think I tried WD-40 once because it works so well for chewing gum and bugs on the paint. But I feel regular Windex works better if you're going to use it every day or so and it doesn't leave an oily film. It's cheaper and you don't need to wash it off your hands. You might want to try it.
BMS black tips
Pretty sure they are all the same yeah, what kind of roads do you drive on? In the UK our roads get so much abuse, so I imagine the dirt allows more carbon to settle on it?Almost 8k miles and my exhaust tips are never dirty.... That being said they also look bigger then normal GTI's. Does anyone know if the Sport or PP cars have larger exhaust tips? I haven't measured them, but they seem larger than normal, but not quite as large as the CSS muffler. Could totally be that I'm crazy. Maybe I'll run out and measure OD and ID and let yall know.
Edit: OD is 3" and ID is 2.5"ish so I think same as stock? They just look larger for some reason.