Originally Posted by function12
buffing can lead to a waving effect in the windshield. I had someone buff a windshield a few years ago. The scratch was gone but now every time you looked through that section the view was distorted. I would either live with it or get the windshield replaced.
If you buff it, you need to use a tool that does a decent job of maintaining the original curvature. You COULD make a home made one with wood, hard pitch, etc. and if there are any local telescope hobbyists, they might be willing to help for suitable bribes.
As for warranty, I'd be willing to bet that very light scratching are not considered faults...
Are you sure it is scratched, or is it just crud left on there by the wipers?