I get your frustration, and I know scratches on the screen are hard to ignore. But the thing is, no one is blaming you for the scratches. As a fellow poster pointed out, cases are a double edged sword. Besides, even though you keep the phone in your shirt pocket, the ginormous screen surface area of the 1520 exposes it to a lot of contact with foreign bodies.
Believe me, it doesn't take a sand paper to get the screen scratched. My brother has a 1020 which he has covered with an Amzer case and put on a screen guard on the phone. However, the curved screen of the 1020 always leaves a small portion on the bottom of the screen uncovered where dust particles accumulate. That area has been badly scratched. But hey, ain't no one blaming the screen guard company or Nokia or Corning, right? It's just the way it is.
The best thing is to forget about it, and use that pretty phone for everything it does offer