Cleaning the Window Fan

I just spent some time cleaning gunk off the window fan - the grate and the blades. We got this phone last summer, and it had accumulated it since then. I didn't use soap or anything, just scraped off the gunk as much as I could.

I can't tell for sure, but it feels like it's more effecient. Probably a good cubic inch or so of gunk sits in the trash can.