In some German districts the waste collectors check the organic waste bin before they empty it. The district of Giessen has metal detectors on its collection trucks. Where the wrong waste is found, the household gets a card. A yellow card tells the residents that they did not sort their waste correctly. With a red card the bin is not emptied. In several places in Hesse, sensors on the trucks scan the inside of each bin as it is lifted. A bin with too much plastic gets a sticker, Falsch befüllt, wrongly filled, and is left full. Having it emptied as residual waste can cost 40 euros.