Old sheet is sort of the basic price for mixed aluminum if I'm not mistaken. If you separated it maybe they'd give different categories. My yard buys all clean aluminum in one category they just call it "aluminum" and they'll take things like aluminum screens, aluminum with a few screws, cast grill tops with the bolt still in it, crutches with the plastic and screws still on, and other stuff that would be considered dirty elsewhere as clean. For windows all you have to do is bust out most of the glass and they'll take the whole thing as clean. A few weeks ago I brought in 3 door frames from an industrial freezer I had scrapped and they deducted a lb cause I left a little too much glass on it but that was it. Anything with too much contamination goes as dirty.