My wife only cleaned the car once - you know those little square sponges which are rough on one side and smooth on the reverse?
See used the abrasive side to clean some bird muck off the bonnet of her Corsa (not my cars thank god).
Made a right mess - looked like she had used sand paper
The local car paint garage used a buffer to take a layer of paint off so a respray was avoided.
Now I clean her car and I sometimes wonder if it wasnt some kind of sneaky feminine trick so she doesn't have to?
You know it makes sense! 
