Glass Wax and the Window Wonderland!
Hey, whirlcool, you and I must both be the same age (mid-50s), since I also remember not only the Glass Wax, but also the stencils. You dipped a sponge into a dish of Glass Wax, dabbed it into the stencils, let it dry, and (assuming your windows didn't sweat like ours did) carefully peeled away the stencil for "beautiful holiday designs that turn your home into a Window Wonderland!" (I even remember the commercial--I think George Fenneman, who was Groucho Marx's sidekick on "You Bet Your Life," did the voice-over for Glass Wax commercials in the 1950s.) Our windows sweated, so those beautiful holiday designs melted into ugly pink blobs...and the stencils were kept to use with spray snow when we ran out of Glass Wax!