This is anecdotal, but...

We quit using the pink antistatic bags a number of years ago when a
customer complained about a similar phenomenon.  At that time, it was
determined that the "film" was beef tallow.  I do not have a copy of
the information used to determine this.  As I recall, it was
actually our customer that made the determination.  At any rate we
quit using the pink ESD bags and switched to the mettalic bags and
have not had a problem since then.

                                                Jay

> Date:          Thu, 4 Jun 1998 10:33:34 -0400
> From:          Mike Bailey <[log in to unmask]>
> Subject:       Anti-Static Bags

> Has anyone experienced problems with packaging bare PCB's in the
> pink anti-static bags?  We are seeing a "waxy"image transfer from
> the bag to the panel after what appears to be several months of
> storage in a controlled atmosphere.  It is aggravated by stacking
> individually packaged boards on top of each other and has occurred
> on several different surface finishes. The substance can also be
> found on the non-board side of the bag.  Does anyone know of  what
> the coating might be comprised?  Would you predict solderability
> issues etc?
>
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