Abstract: In the manufacture of mineral-wool mats or slabs, the raw materials are melted in a melting furnace and are spun to fibers in a spinner. The fibers, after admixture of a resin binder, are deposited so as to be formed to wool mats in a collecting chamber, then cured, trimmed at the sides and cut up into lengths. Both during spinning and during trimming, cutting up into lengths and a subsequent final inspection and check for defects, waste products arise. In order not to have to deliver these waste products, as hitherto, to a proper dump but, instead, to be able to recycle them direct to the production process, the waste products are broken up into smaller pieces and/or unravelled, heated and then briquetted while hot, whereupon the briquettes, possibly after cooling down and interim storage, are combined with the raw materials which are to be melted and thus returned via the melting furnace into the production process.