I have been using Rig grease on a rag to wipe down guns after use. Works well.
What do they use, if you know, and why is it better than Silicone. (I never was a fan of Silicone)
I have no first-hand experience, but I noticed that "Sentry Solutions" also sells a spray and tub of dry film lubricant or dry film rust inhibitor. So whatever it is, a person could conceivably make their own clothes saturated in it.
Personally, I have not worn out the yellow flannel cloth that Ruger sent me with a blued gun. I don't know what's on it, but I imagine it's silicone. The guns I use and prefer to use the great majority of the time are stainless steel and while I do still wipe them down, they don't need any wonder chemicals to pamper the finish.