Park in a garage at work if you can. Zymol Quick Detail (yep, the blue bottle from target or where ever) or Zano Z6, 2 or 3 microfiber towels, gently dry, quick detail... looks like you just washed it

There have been many times fellow coworkers and my boss have walked by while doing that... they were all and I was thinkin you just don't get it

And if it makes you feel any better, though it probably won't, I washed both the X5 and M3 Sunday night.