If you want your paint and exterior plastics to stay looking nice, then avoid the automatic car washes, and the brushes at the self-service bay. Both will scratch the paint, and as @
2014RubyRed mentioned, the chemicals used are harsh and will bleach out your plastics over time. Some of the worst cars I have seen are the ones that go to the touchless washes weekly. In order to clean without using brushes, the chemicals are especially harsh and can turn black plastic to gray in a few years or less.
The best way is to wash is to use a pressure washer to get most of the dirt and mud off before touching the paint. A foam cannon also helps get lots of suds on the paint to provide lubrication when you do use a wash pa to clean the paint.
It you do not have a pressure washer, or do not want to or even cannot wash at home, head to the Pay-N-Spray and use their pressure washer, but only on the rinse setting to avoid the harsh chemicals. Then, bring your own warm water in buckets with lids and use your own pH-balance car wash shampoo with a synthetic wool or microfiber wash pad.
-Dan
---------- Post added at 08:34 PM ---------- Previous post was at 08:31 PM ----------
Same here if I'm in a hurry. I just make sure to spray down the brush first to get all the dirt and sand out after the previous a-hole used it to clean his jeep tires after his trip through the mud hole.
Some friendly advice:
I think you will find that since you just polished your paint to a very high level of shiny awesomeness, that you will quickly notice that any type of brush at a car wash will indeed cause scratches, no matter how clean the brush is.
-Dan