Decide whether you want your ductwork to blend in with the rest of the ceiling or stand out in an artistic way. Blending the duct work in will allow for more design options, while highlighting it with a contrasting color will create modern industrial decor.
Sweep and vacuum to remove any dust, debris and cobwebs. Wash wash the ducts with water and multipurpose cleaner.
Cover the floor and any furniture with a drop cloth to protect it from paint. Tape off all areas around the ducts that should not be painted the same color as the ducts.
Spray primer onto the ducts, following the manufacturer's instructions, and allow it to dry. Spray paint the ducts and allow to dry.
Choose a pattern or color of contact paper. There are many types of patterns available, including like wood grain, stainless steel, geometric patterns and floral patterns.
Measure the length and width of the ductwork to determine how much paper you'll need to cut. Measure and mark the paper on its backing with a permanent marker. Use a utility knife to cut it.
Peel back one corner of the paper backing and stick it carefully to the corner of the ductwork. Slowly peel off more of the paper backing as you smooth the contact paper onto the ductwork.