We are in New York....that's why I asked all of you about mixing the vinegar with the regular fluid. She parks on the streets and that is what creates the big problem....I see her cleaning that window every day.

@DUCHESSA Definitely don't do it then!! I put vinegar and water in a spray bottle to use on my windshield and it froze solid. There's a Preston de-icer that's really good though.

@sewchick57 I guess she will have to use the vinegar only during the summer.

...and "wipers" makes me laugh....so.............

She wants crystal clear windows. BTW, I get the whippers for a dollar and so does she.

Yup. Vinegar is acidic (though just how acidic dilute vinegar in water is, is another matter.) I've used neat vinegar to get lime residue off my car bodywork before now (underground car park, that was dripping something from the concrete ceiling onto the cars.) No ill effects there, but I still don't think it's sensible to expose your car paintwork to it without good reason.