What product or process could be used to polish out a significant
winter scuff of the windshield of our not much driven (80,000
kilometres = about 50,000 miles since new in 2002) Nissan Frontier
pickup .
Scuff is not directly in front of driver, but where the passenger side
wiper sweeps into the top right hand of driver's portion of the glass.
Maybe was grit or dust that got trapped. First time have ever had this
problem.
OR: Would it just be best to change the windshield? Probably at cost
of at least $150?
Any advice or reference to a suitable auto news group would be most
welcome.

PS. Have asked this question 3 times on auto repair forums and not
received any response at all!