A method for analyzing objects depending on their electromagnetic properties. The method including the steps of conveying the objects to be analyzed on a conveyer belt; scanning the electromagnetic properties of the objects and the conveyer belt by an electromagnetic sensor, wherein the electromagnetic properties of the conveyer belt are dependent on metallic contaminants which are stuck in the conveyer belt; generating belt properties data representing the electromagnetic properties of the conveyer belt, and analyzing the objects according to the scanned electromagnetic properties and the belt properties data. This has the benefits that the electromagnetic properties of the conveyer belt are considered when distinguishing between metallic and non-metallic objects which have to be sorted. This way, the objects which got stuck in the conveyer belt over time, may influence a sorting less, which may improve sorting results. Further, an apparatus for executing such a method.