The windshield and wiper blades must be clean to ensure the greatest effectiveness and the longest possible life of the elements since dirt, tree sap and road tar may leave streaking, smearing and wear on the blade when left on the windshield. Washing the windshield with a commercial glass cleaner at least once a month is recommended and wiping the windshield rubber blades with a wet rag as well. It is advisable not to wipe wipers manually across the windshield to avoid damaging the motor and drive mechanism. To remove or do a check into the elements on the wiper blade, push the wiper switch to the lower speed setting and the ignition switch to the ACC setting. When the blades of the wipers are roughly vertical on the windshield switch the ignition switch to OFF. Check the wiper blade parts, the parts are to be replaced in case they are damaged (cracked, broken, or torn). The replacement times will depend on the usage but the ozone will normally destroy the elements in approximately a year. The elements must be changed, preferably in pairs, when the wiper pattern is smeared or streaked, or when the blade chatters across the glass. In case aftermarket blades are being used, note that there are a variety of types of refills, and your vehicle may have any. Aftermarket blades and arms do not always utilize the same or closely similar type of blade or refill, and thus one should pay close attention to the instructions of the part manufacturer. Make sure that the frame jaws are all in place when pushing in the refill and locked because letting the metal blade holder and frame contact the glass during the operation of the wiper may cause scratches.