Lately I’ve had a rash of optical drives (DVD-RW/CD-ROM/CD-RW) that refuse to open without a little nudge from a paper clip via the manual eject mechanism. I’d press the button and hear a soft “thunk” but the drive tray barely budged. All of the drives that have this issue have been belt-driven. The old gear-driven trays were louder, but they worked much more reliably.
After cleaning the drive trying to replace the belt without success, and even trying to replace a drive motor, I stumbled upon an answer so simple I didn’t believe it would work: Wash the belt in soap and water! For good measure, I also used a Q-Tip with rubbing alcohol on it to clean the pulleys. This has saved several drives from the trash heap, and likely many more in the future.
If you have the right tools, you can even unloop the belt, wash it off, and replace it without removing the drive case. Just be careful, and make sure the power is off before you attempt to work inside the drive.
I hope this saves others a bit of sanity.