Cobweb dusters use soft nylon or polyester bristles to collect dust and cobwebs in hard-to-reach places. Unlike traditional feather dusters that catch and hold dust particles in the tiny barbs of bird feathers, modern cobweb duster bristles hold an electrostatic charge that actively attracts dust to the device's bushy head. Because of this electrostatic charge, it can be more difficult to clean a modern cobweb duster than it is to clean a feather duster. The feather duster requires only a quick shake to dislodge the dust, but the cobweb duster often needs to be washed.
Place a dust mask over your nose and mouth and wear rubber or plastic gloves. Take the cobweb duster outside and shake it vigorously. Slap it firmly against a hard surface like a wall or a railing until no more dust comes out.
Form a loose fist and run your gloved hand up and down over the bristles a few times. When no more dust comes out, take the cobweb duster inside. You can take the dust mask off at this point.
Squirt a few drops of dish soap into a sink with the stopper closed. Fill the sink with several inches of warm water. Submerge the cobweb duster in the warm water and swish it around.
Gently run your hand over the submerged bristles a few times to loosen the last of the dirt. Drain the sink and rinse the cobweb duster thoroughly with warm water. Shake the excess water from the cobweb duster and carefully blot it with a dish towel or paper towels.
Air-dry the cobweb duster for several hours in a dish rack or some other place where it can be propped up without flattening the bristles.
If there is a breeze outside, make sure to stand upwind when shaking dust from the cobweb duster.
Don't try to use the cobweb duster when it's still damp. Doing so will make a bigger mess than if you hadn't dusted at all.