Obtain some disposable filter media, roll or sheet, and install it in front of the return air section of the A/C unit on the outside. CHANGE IT WHEN IT GETS DIRTY! This may be daily, weekly, or monthly. Frequency will vary based on room size, other dust collection, what you do in woodworking, humidity, and the "phase of the moon". Leave the factory installed filter on the inside and clean it as needed. 90% of all compressor failures are caused by poor airflow caused by dirty filters and cooling coils. These failures cause electrical burnouts that get blamed on lightning. Simple dirt causes it, not thunderstorms! Filter media comes with a sticky oil on the surface/ This oil catches the micro particles. Cleaning the media does not really give you NEW media. Some will sneak by.