I have two double glazed windows that have misted up inside between the two panes and look awful. I have had a quote from a window company that instead of replacing the windows drill two very small holes in the glass, put in a cleaning solution and then fit two small valves in the drilled holes. This they claim has a 99% success rate. The frames are fine and don't need replacing. Just wondering if anyone has had this done and did it work ? I need to get the windows sorted but trying to keep costs down and not have to have the glass replaced.