Fine scratches on the surface of your windshield are indicative of sand damage. As well as looking unattractive, these scratches might cause potentially dangerous visibility problems. Hence it is imperative to repair any sand damage immediately. This can be done using a relatively quick and easy process without removing the windshield.
Clean the windscreen thoroughly both inside and out. Use a good-quality glass cleaner and lint-free paper towel or old newspaper, recommends the magazine Popular Mechanics. This removes dirt and other debris as well as affords you a good view of the damage.
Attach a buffing-wheel to a variable speed drill. Clean your buffing wheel thoroughly as any debris on the wheel might cause more damage to the windshield.