To clean and maintain wall vents, vacuum dust from the vent cover, remove and wash the vent cover, and vacuum or dust inside the vent as far as possible. To remove the vent cover, use a screwdriver to remove the screws.
Turn off the heating and cooling system before cleaning the wall vents so loose dirt doesn't blow when the system runs. Brushing off the vent cover with a duster or vacuum removes much of the loose dust. When removing the covers, use a small plastic storage bag to hold the screws so they don't get lost.
Hot water and a soft sponge work well for cleaning the vent cover. Use a smaller sponge or sponge paintbrush to fit between the slats. Add mild dish soap if necessary to remove tough dirt or grime. A soak in plain, warm water is another option to remove dirt. Rinse the grate, and allow it to dry before putting it back in place.
If the duct is visibly dusty, use a crevice tool attached to a vacuum cleaner hose to remove some of the dirt. A long, narrow dusting tool is also an option to reach into the duct. Screw the vent cover back in place to complete the cleaning project.