Yes I have. I bought them from amazon, they're basically perspex shed windows, you can buy them in various sizes. I drilled small holes in each corner (carefully, with a really pointy drill bit to prevent splitting) and have nails on the outside of the door and I literally just hook the perspex over. You just need to make sure that it doesn't seal too well, there needs to be sufficient air flow to stop it from getting damp and musty on the inside.