If you've ever taken the time to really look at it, then you know that your home's central heating and air conditioning system is an interesting web of ductwork and supply and return vents, the latter of which deliver warm or cool filtered air to the rooms in your home. Since dust is ubiquitous, it stands to reason that dust also builds up in your ducts and then around your furnace air vents, dirtying the air that you breathe. Make a point of cleaning the vents at least twice a year, or when you notice an accumulation of dust around the slats.
Turn off your furnace before cleaning your vents. Set an old towel on the floor close to the vent. Pop open the cover of the vent by removing the screws with a screwdriver. Put the cover on a towel and the screws in a safe place.
Inspect the vent cover before wrapping it in a towel and taking it to a work area. If it’s covered in dust, tap the vent on the edge of a garbage can. Use a cotton swab to remove stubborn, built-up dust between the slats. Vacuum the vent cover with an attachment on your vacuum cleaner. The goal is to eliminate all the dust from the vent before you wash it.
Combine some mild dish soap and warm water in a small bucket. If you notice black or green stains on the vent, which most likely is mold, add a little bleach to the soapy water. Clean the vent with a sponge and then rinse it under the faucet. Let it dry.
Vacuum the area around the air vent. Reach as far in as you can into the duct with the attachment.
Reattach the air vent covers with a screwdriver.