Well, David Evans mentioned my name as I work in the museum field here
in the UK.  Metal objects are a big problem in some ways.  The main
problem is that if you place it in a plastic bag in an uncontrolled
atmosphere, then you could get problems with condensation and then rust
or discolouring.

Plastic does give off some rather nasty chemicals and gases and
therefore I would suggest using a product called Melinex.  In the
country it can be purchased through Conservation Resources.  We use
this for all documents, posters, prints, etc., and it is inert.  The
company will make up a batch of a special size or you can buy the
materials and make them up using a polyweld machine.  This material
is very strong and is excellent for this purpose.

The main thing, though, is to store the discs in a dry atmosphere with
a relative humidity (RH) of around 45% + or - 5% in any 24 hour period.

Jonathan Holmes