Freeze Girl Scout cookies by sealing the cookies in a freezer bag or rigid airtight container and placing them in the freezer. Frozen cookies generally keep for between four weeks and four months, depending on how well they are packaged.
The key to avoiding freezer burn when freezing cookies is to ensure that they are packaged in an airtight environment. For short-term freezing, a sealed plastic bag or container is generally adequate. If freezing the cookies for upwards of a month, wrap the cookies individually in plastic wrap before placing them in a bag or container, to add an extra layer of protection. Plastic or Saran wrap on its own does not provide adequate freezer protection.
Cookies should be cool or room temperature before they are placed in the freezer. Placing warm cookies in the freezer causes condensation to collect inside the packaging, leading to ice crystals and freezer burn.
Not all types of cookies keep well in the freezer. However, each box of Girl Scout cookies is stamped with a "use or freeze by" date, indicating that all varieties of Girl Scout cookies may be frozen. Some varieties may be eaten while still frozen. Thin mints are a popular cookie to eat as a frozen dessert.