I tried everything from Listerine to car polisher for weeks and nothing really worked well. At the end I made it using two products: (1) Cerama Bryte and using the yellow pads that came with it. It took days of work but I removed 98%. First I thought I made a mess but after brushing and brushing all came out. At the beginning, it looked worse as if thousands of scratches were made to the screen. (2) Polywatch for plastic watches. I use it to polish the screen after cleaning. It is now 90% better than the staingate but you must know that it takes a LOT of effort.
After all type of tests at the apple repair shop, days and days without my computer, all types of diagnostics, including blaming me for what I have active at login, they finally accept to change the trackpad cable. It has been a week, and it is working fine.