Set a handheld hairdryer to the cool or no-heat setting, using the lowest airflow possible.
Hold a section of your artificial ivy in one hand, while gently blowing air onto it with the hairdryer. Blow air onto the ivy from all directions -- turning the vines and leaves, if necessary. Then move on to the next section, and repeat the blowing and turning motion.
Wipe off any remaining dust with a damp cloth or moist cotton swabs.
Place the artificial ivy in a large paper bag.
Pour 1/2 cup of salt or cornmeal into the bag.
Shake the bag gently for a minute or longer. The salt or cornmeal granules will get into hard-to-reach areas to scrub away dust. Repeat if necessary.
Fill a spray bottle with either a 50-50 mixture of water and white vinegar, or a mixture of water and one to two drops dish-washing detergent.
Spray the artificial ivy thoroughly with the cleaning mixture, saturating the leaves and stems. Blot dry with a soft cloth or paper towel.
Protect the artificial ivy's container or planter, if needed, by wrapping it in a plastic bag.
Hold the artificial ivy under cool, gently running water if dust remains. Smaller arrangements may be held under a sink faucet, and larger arrangements under a shower faucet. Blot dry with a soft cloth or paper towel.