My experience has been if they are stored in a more or less airtight container the fogging problem comes back. This makes me believe that the silicone is offgassing onto the glass.A follow up could be the length of time a mask treated in what is determined to be the best treatment to get rid of manufacturing residue before it needs to be treated again because of residue buildup from storage. Should it be stored in an airtight mask box, shoebox, drawer, open air, etc. I add this because I thought I did a pretty good job in treating my new mask in December and was able to dive fog free all week. Then I put everything away for a couple of months until yesterday when I had a pool session. Fog city!