I wash mine ...maybe twice a year...but get your self the filter wrap bag...it covers the pleated filter and you use a rubber band to secure it on top..it helps save the filter big time...and its washable...I just bought some a few weeks
ago since I have a coal stove to clean and the ash is like powder...I think I paid 5.98 for 3 in a bag....
to wash the filter I just blow out as much as I can..then tap it to get some more stuff out...then hose it down and let it sun dry....
AL