I have almost 90K on my cone K&N filter (no, not on my max) and cleaned it. While it was drying I still saw dark spots and cleaned it again and then again.

Three times and still more dirt and red oil came out! Thats a lot of crap in there!

Also, I held it up to the light and no abnormal holes!

Now to let it dry again! K&N rules!

 

Yah, you can't get everything out. There will be stuff embedded in the mesh. I've had the panel for about 45k now, and call me insane, but I've cleaned it about 9 times already. I clean it whenever I see my highway mpg's take a hit. I wasn't gonna do a comparison and spend money on a Nissan filter, but when I had the 60k service they replaced the air filter so I had a new factory one to compare with.

When my K&N is dirty, the highway mpgs drop from 27-29 to 23-25. When this happened last, I popped in the new factory filter, drove from Philly to North Jersey up the turnpike, and yep, 27 mpg up and 28.5 mpg back. Don't be fooled by the propaganda and clean it once every 100,000!!