I bought some scratch removal kit made by Kingston (the computer accessory company) many years ago and still have a few around. It came in with 3 different bottles of polishing paste and one is used first, and then the second and then the third in certain order. I successfully removed a very deep scratch I made when I disassembled my Acer Aspire One netbook many years ago, on the LCD screen. I am not sure if these kits are still being sold, but it was then marketed mainly for the then iPod owners at the time.
Great work on the DM-1701 and other models, by the way! Thanks again so much!