Multilayer ablative windshield

For cars. The glass in front of the driver, that keeps away the wind, rain, bugs and gravel kicked up by that vehicle in front you are tailgating.

Make it in layers sandwiched with a transparent, refractive index matching the glass, explosive substance. When the outer layer has gotten its fair share of gougings and scratchings and you decide that the visibility will be daffinitely be improved if it were clearer,

You press a button on the dash board, not but before taking off its protective cover and reading all the warnings that says "Take care please. Not to operate running road. Is recommended to follow safety precautions first." and that button turns on the juice from the battery to the two conductive coatings which surround the outermost layer of explosive and it detonates and the outer, scarred, useless, layer of the wind(shield/screen) disappears in tiny fragments and you can see clearly through a blemish free glass, clearly, once again.

Or, as buddha_pest has pointed out: "a multilayer glass plastic sandwich ... ten or twenty thin layers should do ; it's important that the plastic not adhere too firmly to the glass, and some sort of mechanism that could grab the edge of (only) the outermost layer of glass, compressing or twisting it, or lifting an edge of it ... something that would make only that top layer shatter, leaving the fresh clean surface of the glass layer below."