1. Get replacement aircon filter. It is usually inside the glove box in the car.
2. Park your car in an open car park.
3. change, and clean housing unit with slightly moist cloth. (If you are allergic to dust, pls use mask.
4. Switch on ignition.
5. Wind down all windows.
6. Turn the temperature dial to Maximun heat (red)
7. Leave it burning hot for 5min.
8. Shut down engine and leave car as is for next 5min.