Hi All,  While I know very little about silicone sprays, I know that
pure silicone grease (Dow Corning 111) has been used very successfully
for sealing pouches for over four decades.  Some of you might recall
the lengthy thread in the Digest back in June 2009 which prompted Craig
Brougher to write the web page, "How To Make Sensitive Pouches", which
is at: http://www.player-care.com/pouches-and-sealing.html 

In that article, Craig covers the pros and cons of five of the common
sealants used to treat pouches.  Pure silicone grease is considered by
most to be an inert substance -- which is one of the reasons it's used
in space.  I have been unable to find any information which indicates
that pure silicone promotes the decay of organic material.

So, perhaps the product that Tom DeLay encountered wasn't silicone at
all -- in fact, in his posting he states that he could clearly see the
brush marks on the leather.  My question would be, "Why are there brush
marks if the product was sprayed onto the leather?" (Just curious.)

That said, there are numerous products on the market that are sold as
silicon spray lubricants.  These products are not pure silicone, and
they generally contain other organic compounds which may indeed degrade
leather over time.  On the other hand, neatsfoot oil, which is usually
brushed on to pouch leather, is known, besides other problems, to cause
the premature decay of leather goods.  So, perhaps it was neatsfoot oil
and not silicone that caused the problems in this case.

Musically,
John A Tuttle
Player-Care.com
Brick, New Jersey, USA