Screen Burn-In Fixer is the most complete app on the store to remove burn-ins.
This app has 3 different methods to remove burn-ins:
• RGB and white:
Runs a sequence of the primary colors (red, green and blue) and white.
• Black and white:
Runs a sequence with the tones black and white.
• White:
Shows just a white screen. Also used a lot to remove burn-ins.
It is also possible to set the amount of seconds a step in the sequence should take.
This app has a diagnostic feature too. You can use this app to spot a burn-in as quickly as possible. This is important because the earlier burn-ins are discovered, the easier it is to remove them. To make use of this feature simply tap 'DO I HAVE BURN-INS?'.