To clean a home's air ducts, mix a solution of water and household cleaner, remove the liners from the duct connectors, and wipe the inner liners with a rag. If desired, use a vacuum to clean the rest of the duct as far as the hose can reach.
Begin by gathering cleaning rags, plastic zip ties, a screwdriver, mastic and a small paint brush, and mix a solution of 3 parts water to 1 part bleach or another cleaner. After removing the outer and inner liners at the wall, ceiling or connecting point, soak the rags in the solution, and use them to clean the duct as far as the arm can reach, and use a vacuum if desired. Use the paintbrush to apply a coating of mastic over the duct connector before sliding the inner liner back over it. Secure the duct connector to the liner using zip ties, and use more zip ties to hold the insulation and outer liner in place over the inner liner. Repeat this process for as many duct openings as desired.
The cleaning process takes around 20 minutes for each duct. Be aware that this method can only clean the area near the ends and connections of the ducts. For deeper duct cleaning, professional equipment is necessary.