By Kasper Jade

Published: 11:00 AM EST

Apple Computer customers who've experienced premature discoloration on the casings of their glossy white MacBooks may finally see some restitution, AppleInsider has been told.

In an internal bulletin earlier this week, Apple for the first time acknowledged that a problem exists with some of its white 13-inch MacBook notebooks, where the casings of the computer may inexplicably turn shades of orange after very little usage.

"Some white MacBook computers may exhibit discoloration on the top case after some use," the company wrote in a note to its retail sector and service partners. "If this issue occurs [...] and the computer meets certain requirements, Apple will cover replacement of the affected parts under warranty."

In order to be eligible for the extended warranty repair, a customer's MacBook must have a serial number that falls within the range of 4H617XXXXXXXX to 4H627XXXXXXXX. The notebook must be irresponsive to approved cleaning solutions.

In replacing the top case -- the affected portion of the computer containing the palmrest area -- Apple will also replace the display bezel, people familiar with the repair process say.

The warranty extension is being made available to MacBook customers in all of Apple's major markets, including the United States, Canada, Europe, Latin America, Asia-Pacific and Japan.

Customers afflicted by discolored MacBook syndrome should contact an Apple Care support representative by phone (1-800-800-2775 in US) or bring their computer to a local Apple retail store to arrange for diagnosis or repair.

Widespread reports of discoloration began appearing only weeks after Apple introduced the new Intel-based MacBook notebooks, which are available in both white and black (not affected). Since then, some customers have had success in getting their stained MacBooks replaced or repaired through a variety of avenues, while others have not.

It's still unclear precisely what causes the discoloration, however speculation on the Web suggests a bad batch of plastics may be to blame.