I saw something on TV this morning on one of the home fix it shows. If you go to the website getthefogout.com you will find there is a method to fix foggy windows. They drill two holes in the pane and spray a chemical to clean the lime build up (through a small hole at the top of the window) then it is rinsed out through a suction tube (thorough a hole in the bottom of the window). I can't find one in my area, but there are several authorized dealers throughout the U.S. Good luck.