To clean polarized sunglasses, first rinse them with warm water. Do not rinse with salt water. To remove fingerprints and smudges, use the Pit Viper cloth or another microfiber cloth designed for lenses. Do not use your shirt or other cloth to clean the sunglasses.
If warm water or a cloth doesn't work, use a lens cleaner. The ideal cleaner should have a pH between 5.5 and 8 and should not contain alcohol.