I would not recommend purchasing somebody's used floppy drive cleaner in a million years. Even ones new out of the box are not recommended. As Thomas suggested, open up your drive and properly clean it out with a small toothbrush/paint brush and a vacuum cleaner. Canned air failing that method. And then take a Q-Tip with something 'friendly' to tape and drive heads (I have used rubbing alcohol & tape head cleaner with great results) and gently swab the heads. Next thing that needs to happen to old disk drives are that the sensor switches near the front of the drive need to be cleaned. I use contact cleaner and carefully spray INTO them and then work up and down with my finger a few times to work the solution in. That way, you'll reduce the risk of 'no disk in drive' error and other strange high or low density probs.
