Richard J Kinch wrote:

Don't be a sucker. "Silicone" spray, such as the Gunk brand you buy at
Home Depot or the auto parts store, is *not* silicone. It is a few drops
of silicone oil in a bulk of petroleum distillate, which is to say, not
significantly different from WD-40. Read the label or MSDS, and you'll
find that silicone is the last ingredient on the list. Actual silicone oil
is expensive, so you won't find it in a big can for a few bucks.

Here is an example:

http://householdproducts.nlm.nih.gov...nds&id=7007009

But here's another MSDS, for Valvoline's Pyroil brand silicone lube
spray:

http://msds.ashland.com/ShowMSDS.asp...CONE+LUBRICANT

It lists:

Ingredient(s) CAS Number % (by
weight)
----------------------------------------------------------------------------------------------

HEPTANE 142-82-5 87.0-
97.0
CARBON DIOXIDE 124-38-9 0.0-
10.0
SILICONE Trade Secret 0.0-
8.0

IOW it appears that there's nothing in the can except propellant and
some silicone compound.