Our yard has a small hopper with a mesh bottom they are dumped in to. There is an elevator connected to it where the operator can pull out the bigger misc. crap. (bottles-wood etc.) It goes up the elevator and drops into a large mesh hopper. The large hopper feeds into a small baler that bales up about 3'x3' bales, which were then stacked till they get a semi load. The scale (digital) is connected to the small hopper. They pull the weight after pulling the trash out.

With it being put into that first hopper they can see exactly whats in it and your standing there while they weigh it, so if there was something dangerous in it, I know they'd escort you off their lot.