The residential and commercial window film has a water activated adhesive system on the side that attaches to the glass. When you use the mounting application solution as required to do the installation, the adhesive is activated by the soapy water solution. Once the installation is completed, it is common for the adhesive to get a foggy or cloudy appearance to it. This is due to the solution activating the adhesive. This process can take from 1 day to 30 days depending on the amount of heat that is hitting the window from the sun. Once the solution has dried out, the foggy and cloudy look will go away. When the fog has completely cleared, you will know that the film has fully cured on the window and can be cleaned.