Reply by syenefarmer

Just buy the washable filter. When I owned that air filter that’s what I did and never had to replace it. When you do wash it you have to let it dry completely before using the filter again. You could buy another washable for backup if you’d like but what I did when I washed the filter was use the OEM paper filter that came with the unit until the washable filter dried. The charcoal filter are supposed to scrub the air of odors so I’m guessing that they’re not really for woodworking applications.