To polish non-touch screen phone

Product plastic tube supplied with a cotton cloth wrapped in a waterproof package.
The manual is almost unreadable, I transcribe below:
1. Using adhesive tape, cover all the painted surfaces so that only the transparent part of the display can be polished.
2. Apply a small amount on the display. Using some cotton or a cotton cloth, polish the scratched areas for 2-3 minutes by pressing loudly. If the lines are deep, reapply several times.
3. With regard to the displays covered with a layer of transparent varnish, it is necessary to polish the transparent portion of the display until this layer has been completely eliminated.
Follow the safety recommendation if swallowed ...
Only suitable for phone screens, MP3 players and PSP. Do not use on touch screens, TFT and polycarbonate (PC).

Used on a digital camera screen, it did not work ...
A word ...