they are not like k&n you cant clean and reoil type thing, they are not "the last air filter you will ever buy". they are a filter that needs to be replaced when it gets clogged. if you blow it out every 6 months or so, it will not get clogged however, the more dirt on it, probably the better the air is filtered. happens with air handling units in hotels, or even at home. it gets finer and finer gaps until it is clogged and you need to clear it out or replace.