  Use one of those 3M Command hooks designed to attach to a wall or appliance until you are ready to remove it. Raise the car window to the closed position and stick the hook at the bottom of the window to hold it in place. It will *not* come off until you need it to, and when you are ready to make repairs, you just pull that little glue "tab" at the bottom of the hook and the adhesive will come off quickly and cleanly. You may want to place that tab at the *top* of the hook instead of the bottom so you can get at it easier when you are ready to remove it. Optionally, you can buy just the adhesive part so you can stick something else on your window if you prefer, but the small hook should do just fine, and maybe you can find another use for it to hang a pair sunglasses or something.  Product Search: **[3M Command Adhesive**](https://www.google.com/search?&biw=2560&bih=1439&tbm=isch&sa=1&q=3m+command+adhesive&oq=3m+command+adhesive)