I'd call the scrapyard if it's too out of your way to just drive by. Know what kind of alloy (6061, 7005, etc) the frame is before you call - I don't know if that makes a difference, but it might. I think calling the scrapyard directly would be more likely to get you an answer than calling the solid waste authority.

Around here, just in the last few months different organizations have started doing scrap metal drives for fundraising - big containers have been popping up all over the place. I don't know who sorts the trash from the recyclable metals when they take those things to the scrapyard, but somebody must.