Nina,
That is great explanation of where we came from and how we got here.  We do
cover our selves with expiration dates and to cover CAP or other regulatory
requirements for expiration dates.  As for never throwing anything away
many of us have gone into laboratories and discovered materials, dry stains
and very dangerous chemicals everyone else forgot.  Years ago I discovered
a bottle of greenish yellow picric acid powder in a storage area of my new
(old) laboratory.  It got people moving and brought the bomb squad.  At the
same time I found some long forgotten stains that I now wish I had to use. 
Pam Marcum


> [Original Message]
> From: nina leek 
> To: ; DeLovino, Salvacion S.

 > Date: 3/20/2002 2:55:39 PM
> Subject: Re: Expiration Date
>
> Dear Salvacion:

> 

> In the old days, chemicals and dyes did not have expiration dates because
they

> did not expire.  It used to be that chemical compounds were assumed to be

> stable unless they were known not to be.  In recent years, the practice of

> putting shelf-lives (?shelf-lifes) on everything has crept in, and now

> everything is assumed not to be indefinately stable.  Philosophically, of

> course, this is true.  In 5 billion years, the sun will expand, engulf the

> earth, and nothing will be stable.  Buy a gallon of water from the
supermarket,

> and you will see it has a shelf-life.  I think what has happened is that

> manufacturers are thinking "liability", and acting to limit it.  Thus,
they

> will test a product after, say 1 year, find it still works, and put a 1
year

> shelf-life on it.  With any reasonable inventory control system, they
will have

> shipped it to a customer long before that, so it is still salable.  Thus,

> acting on the modern philosophy, you should throw them all out.

> 

> On the other hand, you could try them all to see if they work still. 
This will

> probably cost you more than throwing them out and ordering new, but, at
you

> least you resolve YOUR liability issues on this score.  I hate to say it
(I'm

> from Yorkshire, where we pride ourselves on never throwing anything away;
we're

> even meaner than the Scots and the Dutch), but the easiest course is to
chuck

> (sorry, dispose of) the lot.  The only exceptions, I would suggest, are
simple

> chemicals, such as sodium chloride, and dyes that are no longer reliably

> available (such as Alcian Blue).

> 

> Good luck,

> 

> Adrian Leek.

> 

> 

> DeLovino, Salvacion S. wrote:

> 

> >         Hello Histonetters:

> >

> >         What's the usual shelf life of most chemicals and dyes when the

> > expiration dates are not indicated on the container? We have a whole
lot of

> > old chemicals and dyes that we don't know if they're still good or not.
Some

> > date back to the 60's! Thanks in advance.

> >

> >         Salvacion S. Delovino

> 

> 

> 



--- Pamela Marcum
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