<human>: How do you do this: How to keep the airflow vent on a fan clean from obstruction?

OPTIONS:
- Purchase a can of concentrated air and carefully place the nozzle just short of the vent, spray until dust is removed.
- Purchase a can of concentrated air and place the nozzle against the vent, spray until dust is removed.
<bot>: Purchase a can of concentrated air and carefully place the nozzle just short of the vent, spray until dust is removed.