Yes, you can blue and greenscreen virtually anything. You will have to get material in whatever colour you want to use and cut it to size to fit the area you want to put your clouds in. Put it on the outside of the glass so you catch reflections and highlights from whoever or whatever is inside. Then on a good day record some cloud scapes, take them into Premiere and speed them up unless you have access to a timelapse camera. If you have access to any lights you may want to change the lighting inside to react correctly with the way the clouds are changing outside. I don't know where you are but if you are in the Uk, you can purchase a cheap blue screen kit with 2 tripod stands for 36 pounds sterling. The company is called Accord Lighting and they are based in Kent, their website address is
www.accordlighting.com, so they might have something.