Any electrical parts place sells it. It is commonly known as Penetrox
or inhibitor paste. It is primarily used for aluminum wire contact with
terminal strips.
http://bosunsupplies.com carries it (well,a t least one version thereof).
Bosun Supply is an excellent source for all sorts of stuff useful in ham
radio. Besides, when I order from them, I can pretend I own a 40 ft sloop.
grin