1999 Subaru Forester Owner's Manual - Page 119

D In freezing weather, be sure the wiper blades are not frozen to the windshield or rear window before operating the wipers. D Do not operate the wipers if the wiper blades are frozen to the windshield or rear window. If the wiper would be operated with the wiper blades frozen to the windshield or rear window, the wiper blades could be worn or damaged prematurely, resulting in streaking or incomplete wiping. Be sure to use the defroster or rear window defogger, if the wiper blades are frozen to the glass. D Do not clean the wiper blades with gasoline or a solvent, such as paint thinner or benzene. This will cause deterioration of the wiper blades. NOTE D The wiper operates only when the ignition switch is in the "ON" or "ACC" position. D Clean your wiper blades and windshield periodically with a windshield washer solution to prevent streaking, and to remove accumulations of road salt or road film. Keep the windshield washer button depressed at least for 1 second so that washer solution will be sprinkled all over the windshield or rear window. D Grease, wax, insects or other material on the windshield or the wiper blade results in jerky wiper operation and streaking on the glass. If you cannot remove those streaks after operating the windshield washer or if the wiper operation is jerky, clean the outer surface of the windshield (or rear window) and the wiper blades using a sponge or soft cloth with a neutral detergent or mild-abrasive cleaner. After cleaning, rinse the windshield and wiper blades with clean water. The windshield is clean if beads do not form when you rinse the windshield with water. D If you cannot eliminate the streaking even after following this method, replace the wiper blades with new ones. Refer to the Wiper Blade Replacement section (chapter 10) for replacement instructions. 3-20