I noticed that I have a small scratch on my Macbook Pro Retina's screen. When this has happened on my desktop LCDs I've used some Vaseline to hide it. While I know that doesn't actually fix it I am looking for a technique to make this scratch less noticeable.
Possible methods depending on the scratch depth.
1- Fill it - for deep scratches.
Fill it with toothpaste! or professional glass filler.
Believe it or not, toothpaste can be used to patch some screen scratches. Actual toothpaste, not gel or paste-mouthwash hybrids, must be used. Users should gently massage the paste into the scratch with their fingers using a circular motion. If done properly, the paste should adhere to the scratch and polish it away. Then, use a soft cloth to remove excess paste from the screen. Finally, use glass cleaner or a special screen cleaner to remove any additional residue.
Petroleum jelly can also be applied in a similar manner, although it may need to be reapplied if a user happens to rub his or her screen and removes it from the scratch. While toothpaste is an abrasive that pares down a scratch, petroleum jelly fills the scratch because it closely matches the optical density of the LCD display.
2- Polish- for shallow scratches
Get the glass polish in any computer or similar store.
Pro..works well on shallow scratches
Con.. you will create a larger portion on your screen with lower transparency due to polishing.