While scanning some dust can stay on the glass lenses., it has no effect but with time it can produce images with bright vertical lines (usually pink or green). A little cleanup of the lenses and you can continue scanning. Also, if the cards are not scanned as easily (speed Β or cards tend to get stuck) its time to clean the rubber wheels.

To clean your scanner you need to use a clean cloth with rubbing alcohol and clean the wheels, skate and lenses carefully. Wait 30 seconds and close scanner.