Sony eReaders feature a scratch proof casing, so worrying about the outer shell of the device should not be a concern. The display, on the other hand, can scratch easily if you are not careful. This is not just a problem with Sony's eReader, but hand-held electronics in general. Should your eReader develop an unsightly scratch, a fix is still relatively easy and should not take too long to complete.
Turn the Sony eReader off.
Apply the display polish, which can be purchased at an electronics store, to the scratched area.
Rub the polish into the screen with a cotton pad. Apply more polish as needed until the scratch has been removed.
Wipe the area with a clean cotton pad to remove any residue or excess polish.