Start with a piece of clean, dry glass. Place the design you want to make under the glass and trace along the edges with Liquid Sculpey to create a border. Bake and cool completely.
Fill inside of the border with Liquid Sculpey. I started with White Liquid Sculpey and added a variety of alcohol inks to create the rainbow window cling.
Bake at 275 degrees F for 15 minutes. Allow to fully cool and then gently peel the window cling off of the glass.