The invention relates to a method for producing a core card (20) with at least the steps of a) providing a reprocessed fibrous mixture having at least the following properties: the Brecht-Holl fine fraction is at most 50% by weight; the Brecht-Holl long fibre fraction is at least 10% by weight; the Brecht-Holl short fibre fraction is at most 60% by weight; and the ISO 1762 ash fraction is at most 20% by weight, b) preparing at least one fibrous suspension, c) processing the at least one fibrous suspension by carrying out at least one de-ashing of the fibrous suspension until the ash fraction of the dry component of the fibrous suspension is at most 15% by weight, and by adding at least one additive to the at least one fibrous suspension d) producing the laminar system from the at least one fibrous suspension.