Someone emailed me with a problem they were having with their disc drives.
My reply is worth repeating here as it may be of use to some of you.

Dave....
> I think I put a damaged disk in there ... made a horrible screeching sound
> .... and kaput.  It doesn't read anything now *sob*  Does this sound like a
> head cleaning problem?  Is cleaning the heads an easy job?

My reply...
Must not speak too soon of course, but if you think it was caused by a grotty
disc, you are not on your own. I have been sent a few bad discs in my time and
they have caused me problems. I always check discs before sticking them in my
drives, but occasionally a disc with tobacco or other such nasties like hair
gets through the check and into the drive.

What  I have is a large selection of 'throw away discs'. When I hear an unusual
sound coming from my drive I will immediately remove the disc and sling it
(after looking at the surfaces to see which side is affected, sometimes the
surface is scratched. I then put in a 'throw away disc' and see if it makes
the same sound (indicating a foreign body stuck in the drive). In this case an
immediate dismantling of the drive is the best option. If not, and the drive
is read/writing discs, I then carry on tentatively where I left off.

If the drive is not read/writing, the next stage is to clean the heads. If I
am in a hurry, I use a head cleaning disc. If not, I dismantle the drive.

Dismantling the drive is not as hairy as it sounds. Usually there are only a
couple of screws holding it together. The old screwdriver soon has them out.
Sometimes there may be a metal plate over the drive. This has to come off. The
heads are located on arms in the centre of the drive. Usually the top head will
lift up enough for you to get a cotton bud soaked in Isopropyl Alcohol (ask
your chemist, they may ask you what you want it for, whatever you do, don't
tell them you are going to drink it!). If necessary, give it a good rub. I
have often used a lot of force on heads that seemed hopeless, so it didn't
matter, it doesn't seem to have done any harm. The head is a piece of what
looks like ceramic material with a slot containing the gubbins set into it.

Once or twice I have had heads that were literally stuck together and required
real force to clean them, they eventually became servicable.

Best of luck!

Chris