Apple has begun a new program for the replacement of the first generation iPod Nano with respect to the aging of its battery causing over heating, which could turn out to be potentially harmful. So, if you are noticing your iPod Nano (remember that it is first generation only) producing a lot more heat than earlier with time, you can claim yours for a replacement now.
Apple has started informing users about this program and suggests users to replace their affected devices which went on sale during September 2005 and December 2006.
You can order yours with this form and get a replacement for free of charge. You’ll have to give the serial number of your device and if it fits the conditions for being eligible, you’ll get a new device in 6 weeks after yours reach their hands.
One more thing to note is that, if you are having a personalized iPod Nano to be replaced, you’ll lose all the changes and will be getting a new fresh device unit.