While there are chemical-based products capable of dissolving silicone, all are extremely caustic and thus are apt to damage the surface of your RV. If you're curious, check out General Electric's Sealants & Adhesives website.
As a result, most people use putty knives, chisels, screwdrivers, and so on. The bottom line: there aren't any quick solutions for removing silicone-based adhesives. However, if you use the right tools and experiment a little, you should be able to strip out the old stuff in a reasonable amount of time. Best of luck in your efforts.
2004 Winnebago Brave 34D with the usual add-ons