Today, Christmas 2013, I finally totally gave up on the optical drive in my 2007-vintage 17-inch MacBook Pro, the old non-unibody kind. It's a good computer which has performed mostly well, but the SuperDrive optical drive went through a long, slow decline in its ability to mount a disk. I would insert a CD, the drive would pull it in, chug a few times, emit a predictable series of grunts and moans, then eject the disk. At first it was rare, then it became common, and recently it rejected almost every disk I inserted.
A new drive costs about a hundred bucks and I was ready to pay it and try to install it myself, but I'm glad I first tried to see if there was any hack I could try. Indeed there is a hack, a super simple one. I had suspected that dust might be covering the lens so I had tried to blow air into the slot, and also draw air out of the slot, but that didn't help.
No longer afraid to break the drive -- because it was broken anyway -- I deigned to try the brute force method and jam an object into the drive, wiggle it around, and hope that helps. I followed some directions which suggested a business card so I stuck one in there, slid it back and forth, and tried to focus on the left side of the drive where the lens should be.
Lo and behold! The drive now works as expected. Try it if you have nothing else to lose.