The washer spray direction can be adjusted by inserting a pin into the nozzle and turning it to the desired position. Intense heat from the sun, snow and ice, road oils, and the chemicals used in windshield washer solvents combine to deteriorate the rubber wiper refills, which should be replaced about twice a year or whenever the blades begin to streak or chatter. If the wipers are not cleaning the windshield properly, typically only the refill needs to be replaced, while the blade and arm usually require replacement only if damaged. It is generally unnecessary to remove the arm or blade to replace the refill, although positioning the arm higher on the glass may be needed by turning the ignition switch on and operating the wipers. Various types of refills exist, and aftermarket blades and arms may not use the same refill as the original equipment. Most Anco styles utilize a release button to allow the refill to slide out, while some require inserting a small screwdriver to release the refill from the retaining tab. The Trico style unlocks at one end by squeezing two metal tabs, allowing the refill to slide out, and the polycarbonate type is held in place by a locking lever that, when pushed downward, frees the refill. The Tridon refill has a plastic backing strip that can be removed by twisting and pulling up while gripping the blade on a hard surface. Regardless of the refill type, ensure that all frame claws engage the refill and that no part of the metal frame contacts the windshield before operating the wipers. To remove the arm and blade assembly, raise the blade end of the arm off the windshield and move the slide latch away from the pivot shaft, allowing the wiper arm to be removed without tools. For installation, push the main head over the pivot shaft, ensuring the wipers are in the parked position and the blade assembly is correctly positioned, then hold the main arm head onto the pivot shaft while raising the blade end and pushing the slide latch into the lock under the pivot shaft head before lowering the blade to the windshield, checking that the slide latch is fully in place if the blade does not lower.