Until a few decades ago, clays were always supplied in lumps, just as they were dug with a spade or from an excavator-shovel. These days clay blends are normally supplied, these consisting of between three and ten individual clay-types. These blends are shredded, in order to promote their homogenization and to make further processing easier. A standard shred-size of < 10 cm results from the use of a roller-crusher. Witgert is also the only supplier of very finely shredded clays and clay blends of size < 12 mm, which can be broken down considerably more easily in subsequent processing. Lumped clays are exclusively delivered in loose form by lorry/truck, rail or ship. Shredded clays and clay blends, however, can also be packed in big bags with a filled weight specified by the customer.