Why is it you cover the rear wipers with a bag before the wash? Just curious the reason behind it? I've never seen any other place do that.

I have no idea either . They put it on mine too

Hi Robby! Some vehicle models are extra attracted to our wash and like to hold on and not let go (if you know what we mean). In order to protect your vehicle's wiper and our wash, we place a biodegradable bag over your rear wiper. Switching to biodegradable plastic bags helps everyone. Curious about the science behind how biodegrading works? 1.) A special additive makes the plastic film react to UV light and degrade. 2.) After exposure to light, the film attracts microbes that further degrade the film into biomass.  If a plastic bag falls off a car, its direct sunlight exposure forces a microbe-rich environment, and the bag should biodegrade quickly. Thank you for your question!

So the spinning parts of the machine don't get caught in the wiper arm potentially damaging it