Ok...bought Zagg smudge-proof screen as recommended in an earlier post. It was bad, pixelated, prismed, blurry. After a week I took it off. Can you believe that sticky backing to the Zagg screen corrected my "worn spot" issue?
No longer is there a spot that accumulates finger prints easier, gets tacky or clearly is revealed when breathed on. The entire screen is silky smooth.
In other words, rather than my having a worn spot, I now realize I had a "corrupted" spot with funk on it, that I now suspect was related to use of a rubber tipped stylus. Cleaning the spot with water and micro-fiber towel did not fix, nor even my use of Goo-Off as a last resort, but the sticky backing on the Zagg protector was enough to do the trick.
Problem solved... Now working on the Zagg protector return.