Re: How to Clean a CD....

----- Original Message -----
From: "Bill William" <iodideshi@yahoo.co.jp>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, June 24, 2005 2:23 AM
Subject: How to Clean a CD....

> --- Christina <darvida@gmx.at>
>
>> What it the right way?
> ???
>
> Hummm, Digital Talk...?
> Well, I need to know how to wash the dirt and boogie men
> off of an old CD that contains alot of old alt Photo
> stuff. It was a gift from a friend (Thanks RS) so I don't
> want to ditch it.
>
> What is to be carefull about? water? soap?
> Solvents?
> I am sure abrasion would not be the best thing for it but
> can I use a sponge or wash it with fast running water?
>
> Steam?
>
> Acetone?
>
> OK...Yes, I was wrong to leave it out uncovered for 6
> months but I got distracted and forgot return to that part
> of the house.
>
> What can be done?
>
> Ray
>
  If I may drop my pennies in this thread.
  CDs and CD roms are read through the clear side. this side
is vulnerable to scratching which can disrupt the light beam
from the laser. The label on the back is there partly to
protect the reflective coating there. Its tougher because of
the protection but damage to the reflective coating will
also make the CD unplayable.
  I would treat the CD even more gently than a lens because
the plastic is much softer than glass or lens coating. It
can also be damaged by a wide range of solvents. Diswashing
detergent in luke warm water is probably the safest cleaning
agent. I would blow off any loose dust and then immerse the
CD in the detergent and very gently swab the surfaces with
either cotton balls or wadded up cheese cloth. Then rinse
them and dry with the same material. If the clear surface is
not scratched and the reflective surface is intact the CD
will play fine. Because the system is designed to be
tollerant of a limited amount of surface damage or dirt its
possible for a CD with some fine scratches to play OK. The
little dots forming the data are on the surface next to the
reflective layer. The clear surface is slightly out of focus
to the sensor which has the effect of suppressing surface
damage if it isn't too bad.
   Some surface damage can be removed by polishing the
surface, that's what the expensive CD saving machines do.
There are also computer programs which can perform some
error correction on damaged CDs but they won't work if there
is too much data missing.
   The chances are that if no one has tried to wipe off the
dust with a cloth the surface is undamaged.
   BTW, the only unplayable CDs I have were damaged by a
defective CD drive. The scratches are so deep that I have
been unable to polish them out.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com