That's a bit cheeky!

 

On our return from a short holiday, we found this business card slipped behind the rear windscreen wiper of our camper van. Mary was (mildly) offended though we both agreed the car looked far from pristine and clean. While I just chuckled at the cheekiness of it all, Mary went for a sponge and bucket of water to clean the rear of the van! So now it looked well cared for provided you didn't look at the sides, front, or roof of the van! An example of the idiom, sweeping something under the carpet (or rug, if you are American).

As a general rule, I don't see the necessity for spending time and/or money cleaning the outside of a vehicle. There are probably a few reasons why you would want to wash the car: e.g. if it was being used for a special occasion such as a wedding, to remove bird faeces that corrode the paintwork, or as a paid task for a child to earn pocket/sponsor money (bob-a-job).

On the negative side, it wastes a valuable resource (potable water), pollutes the environment (detergents, waxes), and, on a personal note, I can think of many things I would rather spend my time on (such as writing this blog!!). Somewhere in the region of 100 - 300 litres of water will be used to wash one car. According to this study, the combined carbon footprint for drinking water production (0.5 kgCO2eq per 1000 litres; range: 0.18 to 0.79) and wastewater disposal (0.8 kgCO2eq per 1000 litres; range: 0.51 to 1.14) is around 1.3 kgCO2eq per 1000 litres. A carwash, therefore, has a carbon footprint of between 0.1 and 0.4 kgCO2eq provided you didn't drive to the car wash. In itself, not a big deal unless you are doing it week-in and week-out.