Reader Ned Mitchell find his MacBook's media drive is a little picky about the discs he inserts. He writes:
My MacBook's internal CD/DVD drive reads DVDs just fine. However, it's less tolerant of CDs. Sometimes it loads them, other times, not. For example, in iTunes I can rip two CDs in a four-disc set but the other two discs are ejected shortly after I insert them. Any suggestions for a fix?
This isn't an entirely unusual problem--Apple's discussion forums have several threads devoted to the topic. Some have suggested that it can be fixed by reinstalling the Mac OS or zapping the computer's PRAM (start up the Mac and hold down Command-Option-P-R until you hear two startup tones, then let go of the keys and allow the Mac to start up normally). But these aren't sure-fire solutions. More likely, the drive's lens is dirty or the drive is simply broken (or nearly so).
If your MacBook is still under warranty or you have AppleCare for it, put it in Apple's hands. The company isn't shy about replacing these drives when they exhibit such behavior.
If the Mac is out of warranty you can try fixing it yourself provided that the problem is related to a gunked-up lens. You can purchase drive cleaning kits that are intended to brush away crud from a drive's lens. Some people have also had success using a can of compressed air to blow dust off the lens. Others say it's worth wrapping a credit card in soft cotton cloth, applying some denatured alcohol to the cloth, and swiping the cloth-covered card in and out of the drive slot a few times. Still others recommend that in order to do the job right you open the Mac, extract the drive, and clean the lens with a Q-tip and denatured alcohol (iFixit can show you how to open your MacBook and remove its media drive).
If nothing you try works, it's time to look at a replacement drive. An internal replacement drive will set you back around $100 and requires that you remove the old drive and install the new one (again, iFixit will show you how). If you don't require the convenience of an internal drive, you can purchase a compatible external USB drive for around 30 bucks.