On the grasshopper I have the inner filter is about $20 and the outer is $30. I don't mind buying a replacement once a year but in between that time I thought I could wash it instead of taping the dust out. Like I said the Kubota backhoe manual says I can wash it up to 6 times. It and the grasshopper air filter look similar. Both have Kubota diesel engs., one 35hp the other 25hp. Some seem to think a dirty air filter works better then a new one. I have my doubts about that. I have 10+ acres to mow. I would like to put a clean air filter on the eng. every time I mow. Sounds crazy to some I know but if I get two or three filters I can wash them and rotate one each time I mow. I just thought I would get some opinions on this. Thanks